Not A Bug Dress down didn’t remove magus of the moon ability

[Mayhemdj]

Opponent had magus of the moon in play making all non basic lands mountains. I played dress down which should remove that ability but it did not.

 

[Akaleth]

This is working correctly. Magus' ability to change the land types applies in layer 4, but Dress Down doesn't apply until layer 6. It's very unintuitive, but this is correct.