All my nodes are seeing similar pattern of allocated disk usage drop on the graph and grossly reducing reported bandwidth use.
Is this some sort of reporting issue from the satellites?
Yes, quite usual, don’t worry, amount for payment will be OK
I’m not bothered about payment (I’ve waived my payments for the time being).
Just wanted to make sure there is nothing dodgy going on with the network 
The avg calculation chore likely on US1 is longer than 24h. It should backfill when finished, unless it’s failed.
In the case if it’s failed - the gap will remain.