it works for me. I've replicated. Interesting. Ok.. Pro channel appears to not be applied. It removes the zeroing of the output level from the FX chain (raising it to 0 from -inf). It's as if the Pro Channel isn't applied. Also it modified it.
I think this qualifies as needing more info and perhaps a bug submission.
Ok, first test, I pulled the output to -inf and applied Freezing. Output of the FX Chain went to 0 and the track froze. The FX were not applied. If I bypassed the PC at that point the track plays without any PC FX.
Next, I turned on the compressor and pulled down both input and output on the PC FX Chain plug. After bouncing, both input and output faders were zero'd on the FX Chain PC Plug. The compressor PC Plug was still enabled.
If freezing doesn't apply PC by default, at least it shouldn't modify the FX Chain PC module settings.