The former, that were you can get Hellenic.
So I should have got the event, since I was a Greek/Orthodox male emperor.
Since it didn't fire for me, I just edited the file, so it can not happen to AI, set the MTTH to 1 months and deleted all modifiers and requirement.
Then it did fire immediately, but the event chain didn't sadly progress.
Also the same problem with roman culture happens, many of my vassals go roman, but not me. But this is no problem, with the convert to culture of capital decision or just educating your heir by a roman.
This is the problem with multiple mod compatibility. I assume because you can use your study room with "My personal castle", some flag gets sat, which blocks the event chain for me.