Strange linking between parts

Hallo all!
I have this strange problem:
when I explode chords in score editor, the resulting parts are all linked together and it is impossible to separate them on different instruments: changing one change all of them. I tried anything, Ctrl U, K, saw in forums but nothing. I don’t know if it could be a bug.
thank you

if I change instrument even the other tracks change in the same way. I found that this behaviour concerns only instrument tracks, not midi. So for now I’m using midi tracks to explode chords…

Good chance the issue is caused in the Project Window & not the Score Editor. Look at the MIDI Parts in the Project Window that correspond to the Notes that are acting weird. Are they perhaps Shared Copies? If so then any change made to one will occur in all the shared copies. You can convert them back into regular Parts. But I’m not at my DAW for the exact command for that

at first I tried to figure if they were shared parts and also to ungroup track versions but nothing worked that way…