Noticed this on some sites this morning
Some UK sites only. What is this?
could be local network issues (unlikely because all would show this chequered pattern in the hourly) or upload issues.
One of my local sites in Melbourne has a similar anomaly about 6 hours ago here.
Probably a server problem migrating to software for 3.8 but that’s for obj to tell i’m merely guessing 
We had an outage on one server overnight (and unfortunately some of the monitoring was broken so it took a while to notice the problem); it’s back up now.
Yes, came across this problem this morning when I checked my sites - main one had the problem and test site was still fine.
On checking, main site looking at piaware/map/stats etc said it was all talking ok with mlat etc showing a/c on local view - did a reboot and it did come back - was previously showing ‘log empty’ on FA site - shame we have lost that data though!