If you set it to 0 it generates random IDSo what i've noticed is:
1) Zones and map markers do not disappear (you are aware I know)
2) The NPCBases have unique zone IDs
Since they have unique IDs and the zones are not disappearing, if a new one of the same type of base spawns, eg test1, it will not have the zone added to it.
Would it be possible to make the bases just automatically generate a zone ID? I think that would solve the issue if the other fix for zones not disappearing is a while off.