Game Version: #158041
After you place a Town Centre / Mill in between enemy farms, villagers used to convert the farms after Town Centre / Mill is complete. But now they start attacking nearby farms instead. If you reassign them manually they convert the farm.
Serious issue here, since it would be better for them not to attack farms at all and simply stand there. Having villagers taking ownership is the expected behavior which by the way should apply to all game modes.
This is already in our radar, thanks for the report 