I have noticed the verbatim copying of my "description" notes on a few trees from back when mine was public - I wondered (don't know) if maybe, when merging a person's profile, the timeline entries go with it, including descriptions. I know that attached documents do not carry over, and some dates do carry over (e.g., birth and death dates), but maybe descriptive notes are merged over to the other tree? Otherwise, it seemed to me that it would take a whole lot of work to reproduce the notes exactly (although certainly not impossible).
So, maybe there is a semi-innocuous explanation, although I do understand why it bugs you. The only upside I can see is that others who copy from that other tree will at least be getting accurate information passed along.