[Observium] Empty alert check page

Hello

After i upgraded to 11518 (from a 106XX) the Alerts check page is empty. I attached a picture about it. Looks like sometime some page can generate (so example after i press a rebuild or check any category like Devices or Storages sometimes (1 from 10 times) i got the list and all alert listed on the left side, but offen the page is just empty.

Looks like every other things working, just the Alert check page is empty.

Br Laszlo