GryphnnSakashiroI think what's happening there is that settlement kills add some 0.x to notoriety, but the effective total (to be displayed and used to block interstellar factors) gets rounded up to the next integer. And since the decay rate is always 0.5 per hour, it only takes a few minutes for this notoriety to go from 1 to 0. Ship kills on the other hand add 1.0 to notoriety, but only if there's already a bounty on theshipplayer, i.e. the first ship kill is basically free. The first settlement kill apparently isn't.
At this point I just feel ignored, that's exactly what I have said.
No, you said it gets rounded up if >0.5.