Okay, I guess I found the answer myself:
Those two AAFs are not referenced to the same files, which is very likely why Resolve can’t copy the grades.
In timeline 1 I was working with DNxHD MXF files, produced by the Media Composer when exporting the AAF (originally the material in the Media Composer’s timeline were AMA linked R3Ds).
Then I decided to convert those parts of the clips I needed with Red Cine X to ProRes444 files – keeping the same file name but not excatly the same starting TC.
So my question now changes: Is there a way to “tell” Resolve that though these files are different in lenght and Codec they are still the samein terms of the relevant content (the actual image) and that these grades ought to be copied automatically instead of using copy paste?
But maybe I was wrong in the first place to transfom the files from RED RAW to ProRes444 anyway.
I’m on the current Mac Pro Dual 6-core 3,06 GHz, 24 GB RAM, Quadro FX4000 as GPU, NO Red Rocket, and I am working mainly with 4K material coming from an EPIC.
Still figuring out a reasonable workflow …