That's strange! Does this keep happening if you resize the window, by a tiny margin or even switch between maximized and windowed?
Viewing post in BUG: Menu Items are "bouncy"
Hmmm... you're on to something there -- switching between maximized and windowed and back doesn't cause the issue to go away (also resizing by a tiny amount does not appear to fix it).
But the behavior does seem to go away below a certain size point (not particularly usable ones IMO, and resizing back up or maximizing above those points brings the issues right back again).
So, it seems to be a constant related to the size of the window -- it looks like anything at or above about 1891 x 1072 seems to cause it (not exactly that size, but that's the smallest size where I noticed it), and anything below 1713 x 910 seemed to not have that issue (again, not exact sizes, but that's where I noticed it).
Also, it seems like the two different menus have the issue appear at different sizes -- like I found a size between those two where the file menu was stable, but the materials menu was still bouncy IIRC.
My desktop is Windows 10 (x64), 1903 (OS Build 18362.1016). -- (I feel like I saw this happening on my surface book 3 too though, but that's taking forever to boot, and pretending the keyboard doesn't type keys, so that's an exciting discovery that I made today... 😅😅😅)
Anyway, my desktop monitors are at 1920 x 1200 (16:10), 125% scale, and set to landscape. -- The surface is basically the same settings, but I think the resolution is a bit higher.
The app is also set to UI and gizmo scale of 1.25 in it's own settings (because otherwise it's too tiny -- on my desktop 1.0 is almost usable, but on my surface, it's like so tiny I can't even read the menus...).
...
...
Hmmm... looks like this is specifically related to the 1.25 UI scaling ratio (at least on my desktop), because if I change it down to 1.00 (too small) or 1.5 (too big), the issues seem to go away (at least at this resolution?) -- Maybe somewhere there's an integer rounding issue happening for the Y position of those elements?