I keep coming across this problem randomly in my documents.
I’d like to Free Transform → Perspective Transform, but the option is grayed out.
If I hit Ctrl/Command+T and then drag one of the handles while holding Alt/Option, I’m not able to move each handle independently (Perspective Transform). It reverts to the Skew transform which is not what I want (see image).
I can do this in certain documents but not others. I should mention that I’m trying to transform a linked AI file in PS. However, I’ve done the same thing with a linked PSD.