This Bible contradiction is from the Skeptic's Annotated Bible.

Verses

Zechariah was Iddo's son.

Ezra 5:1 View context

Then the prophets, Haggai the prophet, and Zechariah the son of Iddo, prophesied unto the Jews that [were] in Judah and Jerusalem in the name of the God of Israel, [even] unto them.

Ezra 6:14 View context

And the elders of the Jews builded, and they prospered through the prophesying of Haggai the prophet and Zechariah the son of Iddo. And they builded, and finished [it], according to the commandment of the God of Israel, and according to the commandment of Cyrus, and Darius, and Artaxerxes king of Persia.

Zechariah was Iddo's grandson .

Zechariah 1:1 View context

In the eighth month, in the second year of Darius, came the word of the LORD unto Zechariah, the son of Berechiah, the son of Iddo the prophet, saying,