Same problem here! Both in FS2020 and FS2024.
I don’t think it has to do with the buttkicker. I have one too, and a motion rig - so there is plenty of movement. But the phenomenon you described started something like two weeks ago, i.e. before release of FS2024.
Today, I placed my mouse on a table beside the sim, so it is not affected by any movement. And guess what? I get the wandering pointer again, right in my face, at times when I least want to cope with this stupid problem.
I think we need to file this with ZenDesk…