Let's look at why. In non-leap years, Tzav is always read on the Shabbat before Pesach, which means it always gets the special haftarah for Shabbat Hagadol. In leap years, Tzav is always on the Shabbat before or after Purim. The Shabbat before Purim is always Shabbat Zachor (which also has a special haftarah). The Shabbat after Purim is Shabbat Parah (with another special haftarah) the majority of the time, but not always. Shabbat Parah is defined as the Shabbat before Shabbat Hachodesh, which is the Shabbat on or before Rosh Chodesh Nisan. So in years (like this year) when Pesach starts on Shabbat, 1 Nisan is also on Shabbat (and is Shabbat Hachodesh), so 23 Adar (II) is Shabbat Parah, and 16 Adar (II) is an extra Shabbat after Purim without a special haftarah. And if Pesach starts on Sunday, 1 Nisan is on Sunday, so 29 Adar (II) is Shabbat Hachodesh, 22 Adar (II) is Shabbat Parah, and (in unwalled cities) 15 Adar (II) is an extra Shabbat without a special haftarah. (In walled cities, 15 Adar (II) *is* Purim, so the haftarah for Zachor is read again.) If it's a leap year, then that extra Shabbat is Tzav.
Those cases add up to 13.9% of all years in unwalled cities, or 10.0% of all years in walled cities. Ok, that's not *that* infrequent, but they're not so evenly distributed. Here's why. If you have one leap year followed by two non-leap years (the most common configuration), that's a total of 37 lunar months, which comes out to a whole number of weeks plus 15 hours 181 chalakim (i.e. less than a day). Because of the limited number of days of the week when the major holidays can fall, this means that it is very common for the holidays to fall on the same days of the week for 2 or even 3 consecutive leap years. So you can have multiple leap years in a row when Pesach starts on Shabbat or Sunday (and Haftarat Tzav is read), and then a long drought when that doesn't happen.
So Haftarat Tzav was read in the following recent years (the asterisk means unwalled cities only): 1978, 1981*, 1992, 1995, 2005*, 2008*, 2016, and 2019. (Note that walled cities had another 21-year gap from 1995 to 2016). After this year (2022), the next time will be 2043! And then 2046, 2049, 2052*, and 2073 (with another 21-year gap for everyone, and a 24-year gap for walled cities).
(Cited from the Facebook group, "Hebrew Calendar Facts" on March 18, 2022. Thanks to Gideon Klionsky for bringing this to our attention, who in turn credits the classic "Why is this year different from all other years?" by Ari Meir Brodsky)
The main source of information concerning Jeremiah’s life is the biblical Book of Jeremiah, which records that Jeremiah was born to a priestly family in Anathoth. His ministry began in the 13th year of the reign of King Josiah, who ruled the land of Judea in the seventh century BCE.
Jeremiah lived at a time of deep upheaval in Jewish history, most significantly the destruction of the First Temple in 586 BCE and the exile of the Jewish people to Babylonia. Much of the Book of Jeremiah is a lengthy tirade against the people for their faithlessness and ominous warnings of the destruction to come if they do not mend their ways. Jeremiah himself was scorned by the people to whom he preached, arrested, beaten and left in a pit. King Zedekiah, the last ruler of Judah, had him imprisoned for warning of the fall of Jerusalem. Eventually Jeremiah was exiled to Egypt, where he eventually died. According to Jewish tradition, Jeremiah was also the author of the Book of Lamentations.
(לב) לָכֵ֞ן הִנֵּֽה־יָמִ֤ים בָּאִים֙ נְאֻם־יְהֹוָ֔ה וְלֹא־יֵאָמֵ֨ר ע֤וֹד הַתֹּ֙פֶת֙ וְגֵ֣יא בֶן־הִנֹּ֔ם כִּ֖י אִם־גֵּ֣יא הַהֲרֵגָ֑ה וְקָבְר֥וּ בְתֹ֖פֶת מֵאֵ֥ין מָקֽוֹם׃ (לג) וְֽהָ֨יְתָ֜ה נִבְלַ֨ת הָעָ֤ם הַזֶּה֙ לְמַֽאֲכָ֔ל לְע֥וֹף הַשָּׁמַ֖יִם וּלְבֶהֱמַ֣ת הָאָ֑רֶץ וְאֵ֖ין מַחֲרִֽיד׃ (לד) וְהִשְׁבַּתִּ֣י ׀ מֵֽעָרֵ֣י יְהוּדָ֗ה וּמֵֽחֻצוֹת֙ יְר֣וּשָׁלַ֔͏ִם ק֤וֹל שָׂשׂוֹן֙ וְק֣וֹל שִׂמְחָ֔ה ק֥וֹל חָתָ֖ן וְק֣וֹל כַּלָּ֑ה כִּ֥י לְחׇרְבָּ֖ה תִּֽהְיֶ֥ה הָאָֽרֶץ׃ (א) בָּעֵ֣ת הַהִ֣יא נְאֻם־יְהֹוָ֡ה (ויציאו) [יוֹצִ֣יאוּ] אֶת־עַצְמ֣וֹת מַלְכֵֽי־יְהוּדָ֣ה וְאֶת־עַצְמוֹת־שָׂרָיו֩ וְאֶת־עַצְמ֨וֹת הַכֹּהֲנִ֜ים וְאֵ֣ת ׀ עַצְמ֣וֹת הַנְּבִיאִ֗ים וְאֵ֛ת עַצְמ֥וֹת יוֹשְׁבֵֽי־יְרוּשָׁלָ֖͏ִם מִקִּבְרֵיהֶֽם׃ (ב) וּשְׁטָחוּם֩ לַשֶּׁ֨מֶשׁ וְלַיָּרֵ֜חַ וּלְכֹ֣ל ׀ צְבָ֣א הַשָּׁמַ֗יִם אֲשֶׁ֨ר אֲהֵב֜וּם וַאֲשֶׁ֤ר עֲבָדוּם֙ וַֽאֲשֶׁר֙ הָלְכ֣וּ אַחֲרֵיהֶ֔ם וַאֲשֶׁ֣ר דְּרָשׁ֔וּם וַאֲשֶׁ֥ר הִֽשְׁתַּחֲו֖וּ לָהֶ֑ם לֹ֤א יֵאָֽסְפוּ֙ וְלֹ֣א יִקָּבֵ֔רוּ לְדֹ֛מֶן עַל־פְּנֵ֥י הָאֲדָמָ֖ה יִהְיֽוּ׃ (ג) וְנִבְחַ֥ר מָ֙וֶת֙ מֵחַיִּ֔ים לְכֹ֗ל הַשְּׁאֵרִית֙ הַנִּשְׁאָרִ֔ים מִן־הַמִּשְׁפָּחָ֥ה הָרָעָ֖ה הַזֹּ֑את בְּכׇל־הַמְּקֹמ֤וֹת הַנִּשְׁאָרִים֙ אֲשֶׁ֣ר הִדַּחְתִּ֣ים שָׁ֔ם נְאֻ֖ם יְהֹוָ֥ה צְבָאֽוֹת׃ {ס}
(21) Thus said YHVH of Hosts, the God of Israel: Add your burnt offerings to your other sacrifices and eat the meat! (22) For when I freed your fathers from the land of Egypt, I did not speak with them or command them concerning burnt offerings or sacrifice. (23) But this is what I commanded them: Do My bidding, that I may be your God and you may be My people; walk only in the way that I enjoin upon you, that it may go well with you. (24) Yet they did not listen or give ear; they followed their own counsels, the willfulness of their evil hearts. They have gone backward, not forward, (25) from the day your fathers left the land of Egypt until today. And though I kept sending all My servants, the prophets, to them daily and persistently, (26) they would not listen to Me or give ear. They stiffened their necks, they acted worse than their fathers.
(27) You shall say all these things to them, but they will not listen to you; you shall call to them, but they will not respond to you. (28) Then say to them: This is the nation that would not obey YHVH their God, that would not accept rebuke. Faithfulness has perished, vanished from their mouths.
(29) Shear your locks and cast them away,
Take up a lament on the heights,
For YHVH has spurned and cast off
The brood that provoked God's wrath.
(30) For the people of Judah have done what displeases Me—declares YHVH. They have set up their abominations in the House which is called by My name, and they have defiled it. (31) And they have built the shrines of Topheth in the Valley of Ben-hinnom to burn their sons and daughters in fire—which I never commanded, which never came to My mind. (32) Assuredly, a time is coming—declares YHVH—when men shall no longer speak of Topheth or the Valley of Ben-hinnom, but of the Valley of Slaughter; and they shall bury in Topheth until no room is left. (33) The carcasses of this people shall be food for the birds of the sky and the beasts of the earth, with none to frighten them off. (34) And I will silence in the towns of Judah and the streets of Jerusalem the sound of mirth and gladness, the voice of bridegroom and bride. For the whole land shall fall to ruin. (1) At that time—declares YHVH—the bones of the kings of Judah, of its officers, of the priests, of the prophets, and of the inhabitants of Jerusalem shall be taken out of their graves (2) and exposed to the sun, the moon, and all the host of heaven which they loved and served and followed, to which they turned and bowed down. They shall not be gathered for reburial; they shall become dung upon the face of the earth. (3) And death shall be preferable to life for all that are left of this wicked folk, in all the other places to which I shall banish them—declares YHVH of Hosts.
(22) Thus said YHVH:
Let not the wise man glory in his wisdom;
Let not the strong man glory in his strength;
Let not the rich man glory in his riches. (23) But only in this should one glory:
In his earnest devotion to Me.
For I YHVH act with kindness,
Justice, and equity in the world;
For in these I delight
—declares the YHVH.
This haftara skips to chapter 9 to "end with a positive religious instruction--though not the customary promise of national renewal," (The JPS Bible Commentary: Haftarot, p. 155).
Regarding 8:1-3
"This passage carries the image of judgment and death to one more extreme dimension. Not only will there be death, but even the dead who previously have been honored and laid in their tombs will be dislodged. Not only will forms of civility in the present and future be dysfunctional, but past acts of civility will be nullified. Present wretchedness will nullify past decency. Nothing is sacred or honored or beyond the reach of the wrath of Yahweh now unleashed. The punishment here fits the sin: Judah has gone after the gods of the heavens; now the bones of the disobedient dead will be spread before these gods. At the end, life is worse than death (v. 3).
The rhetoric of the text is not "realistic" in the sense that it describes what is known. Rather, it is an imaginative anticipation of what is as yet unknown and unexperienced, for which there is no precedent. But the future is boldly envisioned by the prophet. The judgment to come is so unprecedented that only such ominous images are adequate to communicate it. Biblical eschatology always pushes to the limits of our imagination. Poetic characterizations of God's new age of blessing and poetic scenarios of God's judgment are always extreme cases of imagination, in the NT as in the OT. Such extreme imaginations are to be taken seriously. But when treated as flat predictions or descriptions, they are sure to be misunderstood and distorted. In such a reductionism, poetic efforts are robbed of their imaginative power. Any language that is used must match the unprecedented character of the impending judgment. The language of 8:1-3 does that. Practically, it may have been sufficient to impress upon Judah the impending historical realities of exile and displacement, but the prophet is not engaged in practical reasoning. Jeremiah seeks to penetrate and break open the imagination of the self-satisfied community so that it will see that the present circumstance is so extraordinary in its departure from torah that there can be no business as usual, not for Judah and surely not for Yahweh. Business as usual is dysfunctional because the indignant power of God is mobilized against Judah, and that mobilization is irreversible. This text seeks language to match that awesome, devastating theological reality," pp. 83- 84.