Get-MgUserCalendar doesn't return default Calendar for small # of rooms.

[4Benjamin42]

I recently ran into an issue attempting to get the calendar of a room resource. If I run Get-MgUserCalendar -UserId RoomEmail@domain.com -All the only Calendar that's returned is the "United States Holidays" calendar. This happens for only 2 rooms out of 400+ rooms we have in our tenant. All other rooms will show the Calendar calendar alongside the US Holidays calendar.

If I run Get-MgUserDefaultCalendar I get the default calendar for those 2 rooms and all our other rooms.

Any ideas on why this behavior would be happening?

Note: This happens with the Beta modules as well. Same results.