Calendar content and buttons disappear sometimes (735, Denim, Update 1)

[apoc111]

Sometimes when I open the Calendar app I can't see neither my entries nor the buttons/ellipsis menu and the only way to get these back is if I do a restart. Had done a hard reset but the problem showed up again after couple of days. I even tried to hide Facebook events and weather information, switched Cortana off but nothing helps. This is a very annoying but on a daily driver....