Icebelts don't respawn like CCP said

Recently CCP announced that Icebelts would spawn system specific 6 hours after they are cleared (+some wandering icebelts or whatever) It was very predictable during the last 2 days. BUT

This morning we had an Icebelt that we cleared before downtime at 9:50 NEST
We calculated that a new belt would spawn at 15:50 NEST (+6h)

However after downtime at 13:00 NEST a new belt spawned unexpectantly.
We cleared it at 14:30 and the new belt should spawn at 20:30 (+6h)

However, none of the two predicted belts spawned and now we are sitting here in our public fleet waiting for something that will not show up

There is a 2 hour plus variable added to the spawn time.
So in theory after ice belt is depleted, it will re-spawn from 6 hrs to 8 hrs.
I have noticed the re-spawns at 6 to 8 hrs where we mine Ice.