#1 original
While in a sector containing a planet, if a second planet is near enough to render blocks and appear in the nav map, the blocks of the second planet will render and appear to orbit the first planet. The nav marker will indicate the block location. The distance view model of the planet still shows in the correct location. Screenshots attached to illustrate. Planet blocks will revert to the correct location when leaving the first planet's sector. Did a clean install in separate directory and produced same result.

#2
I had not changed any server settings from default prior to my original post. I tried setting UNIVERSE_DAY_IN_MS to -1. This prevented the displaced planets, but of course also disabled all orbital mechanics. Any other values for this setting simply changes the rate at which the planets move away from their proper position.

I have also since tried running a dedicated server, with client run from the same and separate machines. The only instance when I did not observe this is when the adjacent plants happen to have their rotational axes aligned.

#3
Found 2 planets that have this on the normal test server, sector 73 12 73 (visit this sector to see the problem yourself).

The actual nearby planet is in this case on the opposite side of the sky than the view model. Doesn't seem to happen for every 2 neighbor planets though.