I open the project.
I open the “old” sequnce from 6 months ago into the timeline.
I copy the motionarray clip (animated texts) into a “new” sequence.
I double-click the motionarray clip in the a new sequence.
This opens up yet another sequence with only 3 clips (=3 texts) that form the motionarray.
I edit the texts, then close it.
Unfortunately, the text edits now present in BOTH, the old and the new sequence.