This question was recently migrated from Sustainability.SE to Politics.SE. There was already an answer when it was migrated, and as expected, that answer was included with the migration.

However, back on Sustainability.SE, the answer has this notice:

This answer is hidden. This answer was deleted and converted to a comment 1 hour ago.

The answer was not deleted to a comment, it was migrated and then deleted. The post notice should simply stop after "This answer was deleted."

I confirmed on several other migrated questions with on Sustainability.SE that that same post notice occurs: here, here, and here. I don't have enough rep anywhere else to see if this is happening on other sites.