I've only lately have had issues with generative fill inserting random objects into areas.
I do a lot of image touch-ups and extensions, often not putting anything into the "what would you like to generate" box and just letting the AI fill based on surroundings (often not very large areas).
Recently, I've removed a crane from the sky and it put in what appeared to be a drone. I've extended water and it put in a duck, added some land and put a fox on the land (!!??).
This has only been in the most recent version 26.2.0