I've encountered a problem with Dynamic Link a couple of times now and I've discovered why I'm having difficulties.
The problem is that importing a PrPro sequence into AE with DL returns a blank composition. I can view the composition in the monitor but it refuses to be put onto the timeline.
Why? Because the PrPro sequence contains clips that have been "replaced by After Effects comp" with DL. As soon as the DL-clips are removed, the DL-sequence is usable.
Basically: Dynamic Link inside Dynamic link does not work.
Is this working as intended? How can I use my PrPro sequence in AE?
Yes. You cannot have cyclic links. You need to render those comps in your PPRo project and substitute them again.