I’m new to this place…I still have no idea what’s going on and little idea of what an instance or my instance is.
…but I’m an OG internet user and what you’re describing sounds like EchoNet FidoNet?, or one of the various networked BBS systems pre-internet. BBSs, or groups of BBSs would frequently drop in and out of the networks, and the forums/threads from the absent BBSs would still be there…but in a “cleaved” state. Very confusing to a user who used multiple ‘Nets (which was everybody).