It's not a bug, it's a feature ! OK, it's a bug. After a change of this moon orbit, all orbital units coming from other planets were stuck in a pseudo orbital layer. As the result, you can see about 100 orbital fighters rotating very fast around this moon like a true asteroid belt. (Nota: the light effect is done by a nuclear missile also stuck in orbit) To see it in game, you can just replay this game : 12596646844948700464 at about 30' and after.
I had a similar gravity well "feature" on a strangely built system; three larger planets were closely orbiting a fourth, a tiny lava moon. Nukes would become trapped in the gravity well and spin madly around the center planet to no avail. Someone planet-smashed the lava moon, however, obliterating both... then the nukes started flying. If this were to be addressed, showinga hheatmap of gravity wells to highlight traps, and making orbital units forcibly enter planets they're stuck in the gravity well of would work. I'd say the same for nukes but with random placement, that could get messy... or just fun.
3 large planets orbiting a smaller 1? same system as mine, although i had 2 (or was it 3?) smash-able moons farther out in the system https://forums.uberent.com/threads/the-most-pretty-bug-ever.65287/#post-1024479
Yes ! Exactly the same ! In my case, the system is only three little moons orbiting around a sun. But the moon sent to be crashed was stopped close to the sun...
I've seen this happen in some games as well. Sometimes nukes just spin and spin and spin round a single planet.
Seen that before, that and glass planets where the shift key gets 'stuck' (being seeing that a lot recently). I took these shots because they're actually really pretty, especially the planet with 'rings'.