Since around Month I have following problem when I move mouse coursor over any button at hubitat webinterface.
I testet on Chrome and Opera, the same. This problem is through many recent versions of hubitat.
I've noticed this once in a while recently on (Mac) Edge too... It's not very consistent for me though - just every now and then. But definitely a recent development.
The button gets shaky, but I don't think my cursor gets shaky too -- I don't recall that anyway. When I've seen it, it's not as pronounced as it is in your video, but it is indeed a thing.
It happens on all browsers, Edge included. Its because some element of the hovered button is a pixel less wide than the un-hovered button, so if the cursor is exactly on the edge of the button then it keeps switching between the two states rapidly. It is annoying but also pretty easy to avoid.