For instance, the seed "desert" with 30% coverage generates a non-hostile Tribe Faction with -78 relations. Due to the low relations, there is no meaningful interaction possible with this faction. Can't call 'em on the comms console, won't get raided by them. At best, you can raid them or hope to catch and murder a group of passers-by.
They will send caravans.
They will not send military aid.
They do not really like you, but they don't hate you.
If you mess with them in the slightest, then it's on.
It's fine. Negative relations don't necessarily indicate that the faction is hostile. Thanks for reporting though.
//edit:
nevermind, -40 is fine, but -78 should be hostile, so it's a bug
Wasn't able to reproduce it with that seed, but I've hopefully fixed the issue that could cause low-relation non-hostile limbo factions. Thanks for the report!