Calendar card error and strange view (not always)


I have this problem for a couple of months now, but just now found the time to post about it, made the photo’s couple of weeks ago…

Sometimes I get an error “Could not retrieve events for calendars:” on my dashboards. Reloading the page fixed it (I tnink every time after the first reload), what causes this?

Other problem I have is that sometimes the layout of my calendar looks wrong and takes up more space then when it is correct (photo’s are from an quiet day :).

This is how it should look, a reload usually fixes it, but not always on the first reload:

I have no idea what triggers this…