Wormholes

Yesterday we had the strangest thing I've seen in a wormhole recently, we've got used to closing holes and appearing back in the POS (nice when you're in an Orca) but this was something much stranger.

We had a Grav site, and people noticed their drones disappearing from the overview. So burning over to the spot they were disappearing, we discovered another Grav site, in a completely separate grid with no scannable signature. It was identical to the main site, and even gave the "Average Frontier Deposit" message when warping to it. Just to see what would happen, we anchored two cans right on each side of the edge of the grid crossover, and after downtime today they're still there, anchored within 2km of eachother - not possible usually. And just as a final oddity, there's a brand new untouched Grav site in the spot where the first (almost mined out) site was yesterday.

Has anyone come across anything like this before? Presumably it's some sort of bug that caused the server to spawn two sites ontop of eachother.

Related note: I have seen a grid boundary in the middle of a (IIRC radar, although it could have been mag) site that hid a wave of Sleepers from us for a while. It seems that this case is different, though, in that there are two colocated signatures involved as well as two grids.