I noticed that on web in default state we used defaultEnabledApps instead of defaultWebEnabledApps. This caused the calendar not to be visible to a just logged in user. This was also inconsitent with the fact that in the reduceEnabledApps reducer we set enabledApps to defaultWebEnabledApps on logout.
This was introduced in D9145 and Michał says that it's a mistake.

Tested that the correct default is used now.