Copy/Paste and envelope editing in general went through a massive overhaul. As far as I can see synth automation copy and paste works with no problems in X2.
Do you have a case number for a specific bug that you are referring to? Its impossible to confirm without having specifics, since there are hundreds of permutations of what you can do just with copying and pasting envelopes. Instrument tracks, multi output synth tracks pasting within the same track, pasting from a normal track to instrument track, etc...