Apps suddently stopped sending notifications on my Nexus 7 (2013) running Lolypop 5.0.2

I have noticed that some apps (not all but a select few like Quizbattle and Wordfeud) have stopped sending notifications.

I have checked under App Info that notifications indeed is enabled, and other apps like Email and workout app are sending notifications fine!

I think it started doing this around when 5.0.1 was installed, but not sure. It persists after having installed 5.0.2

Nexus 7 (2013) is not rooted and install was done after tablet suggested updating, and all installs went without issues.

What could be causing this weirdness?

thanx for any suggestions in advance