There is a bug with App tiles, App cannot be accessed. After refresh it works again, but this is not desired state. Apps tiles are not working
And another entry on the same issue - Clicking-an-Power-BI-app-in-service-doesn-t-open-the-app
Interestingly, with only 3 votes, a moderator has already picked up on this issue and started asking questions which are already answered in this thread.