Calendars: Exception thrown for iOS 13 users when adding event(s) to a calendar

We are using AppCenter to gather information about crashes for our app and since iOS 13 came out we suddenly see crashes thrown by this library. On other iOS versions we don’t have this issue with this library.

Exception: Enumerable.Select[TSource,TResult] (System.Collections.Generic.IEnumerable1[T] source, System.Func2[T,TResult] selector) System.ArgumentNullException: Value cannot be null. Parameter name: source

Stacktrace: Main thread System.Linq Enumerable.Select[TSource,TResult] (System.Collections.Generic.IEnumerable1[T] source, System.Func2[T,TResult] selector) Plugin.Calendars CalendarsImplementation+<AddOrUpdateEventAsync>d__8.MoveNext ()

So it seems it goes wrong in the AddOrUpdateEventAsync method in this class: https://github.com/TheAlmightyBob/Calendars/blob/master/Calendars/Calendars.Plugin.iOSUnified/CalendarsImplementation.cs

Is this a known issue?

I couldn’t reproduce the issue myself on an iOS device.