Kaseya placed a temporary fix on our server and the problem looks solved.
Answer from Kaseya:
This is an issue we are currently aware of. I applied a temporary fix on your server. Simply re-process the policies for all the machines missing the Monitor set. Do not reload your hot-fixes or run a reapply schema till the permanent fix is released because this will remove the fix and we will have to reapply it. Our development team is working on a fix at this time. Please be patient.
So if you have problems just add a ticket