I am currently working on a large ship (about 170000 blocks on the main entity, and about 310 blocks long) and have experienced two major bugs involving gravity. Bug A is more confusing and I couldn't recreate it, instead i just worked around it, but ended up causeing Bug B, which i recreated easily, and which is the main issue I wish to report.
BUG A
I originally wanted to have a large area of the ship use a different direction of gravity than the main section, but the only way to reach that section is through an elevator that uses a gravity transfer system involving area trigger modules to switch between the gravity of the elevator and the gravity of the main ship. In most places this elevator gravity transfer system worked seamlessly, but at the very end of the elevator (which was both the farthest from the core and the place that I wanted the gravity to be different from the rest of the ship) gravity glitched out. I would exit the elevator, and for a split second I would be oriented correctly, but then after that I would no longer be oriented to anything, but my ui would give me the standard "you have switched to <shipname>'s gravity". I have no idea what may have caused this or how one might recreate it. The only factor that I think may be involved was that the area this was happening in was around 250 blocks away from the core, but I don't really see why that would cause this. Eventually I decided to create a separate entity docked to the main ship that would have its own gravity, rather than just continuing to edit the main ship. This seemed to work perfectly, until I discovered Bug B
BUG B
My solution to Bug A worked fine until I made the separate entity's floor adjacent to the back wall of the main room of the primary entity, like this:
A B
! A B
! A B <---
V A B
A B
AAAAAAAAAA BBBBBBBBBBB
(the arrows indicate the direction of the gravity in entity A--the primary entity--and B--the separate entity)
If I walked on any surface in entity B other than the bottom most floor while in its gravity, everything would function fine. However, as soon as I attempted to walk on the floor, either I would immediately lose my orientation to any entity at all, or I would be fine for a few seconds unless i jumped, at which point I would lose my orientation as well.
Gravity in side entity A functions completely normally.