The latest 1.26 ArmA3 release has created a number of issues with dedicated servers. I've seen this same mass de-sync behaviour on two seperate servers; hopefully the SimHQ server isn't effected by this...

1.26 Dedi Server De Sync ArmA3 Bug Tracker
Post on BI Forums

This looks worrying .... I guess we will just have to wait and see.

UPDATE - Apparently BI Developers have said that after analysis, the problem appears to be isolated
to the Dev branch only. We played on Saturday for two and a half hours without problems, so it seems to be true.

Yep, there were a few odd moments, but nothing really a problem.

Glad to hear it!