My receiver (-1408236245) stats for today show zero messages from 0:00-1:00 UTC, 2:00-3:00 UTC, 9:00-10:00 UTC and 11:00-12:00 UTC, but I have the usual number of aircraft for all four periods. That they're exactly one hour long and start/end on the hour makes me think this is some sort of hourly data processing job that isn't running properly, not anything wrong with my receiver.