Contradiction with Jeremiah 38:4
This verse contradicts Jeremiah 37:12 by showing that remaining in Jerusalem was seen as betrayal, as Jeremiah is accused of weakening the resolve of the people and soldiers by speaking against staying in the city.
Jeremiah 38:4: Therefore the princes said unto the king, We beseech thee, let this man be put to death: for thus he weakeneth the hands of the men of war that remain in this city, and the hands of all the people, in speaking such words unto them: for this man seeketh not the welfare of this people, but the hurt. [welfare: Heb. peace]
Contradiction with Jeremiah 39:9-10
While Jeremiah 37:12 describes Jeremiah's intention to leave Jerusalem to go into the land of Benjamin, this verse notes the deportation of people, indicating that leaving may not have been voluntary later due to the Babylonian conquest.
Jeremiah 39:9-10: Then Nebuzaradan the captain of the guard carried away captive into Babylon the remnant of the people that remained in the city, and those that fell away, that fell to him, with the rest of the people that remained. [captain...: or, chief marshal: Heb. chief of the executioners, or, slaughtermen]