Render and Replace not importing roto brush masking

Morning!

So I've gone coo coo with Pr and using AE compositions with rotoscoping (roto brush masks..) as dynamic links. Yay!

However going back into Pr and scrubbing through the timeline is about as painful as watching paint dry. The frame rate is long enough for me to get out of my seat and make more coffee and come back, and it's half done watching the frame rates resolve.

So I'm reading here to take those AE clips and change them to 'Render and Replace' so it's embedding in Pr and no more DLs. But the issue is it does not bring in my roto brush mask.

Any tricks or settings I need to be aware of?