A Room or Room List disappears from Outook Scheduling Assistant

This case is really cool, and on a first look it looks like there is some magic involved. Help desk support engineer has escalated a situation with a "problematic" user mailbox and outlook. Whenever this user has been scheduled a meeting in a room or room list, the scheduled room(s) automatically disappears from the scheduling assistant list in a few seconds. It sounds like magic, and I've checked with my outlook, and I couldn't believe my eyes how room(s) disappears automatically in a few seconds when this users was scheduled a meeting and meeting room(s).
So, I've started digging the properties of this users mailbox and bumped on following invalid configuration :

WorkingHoursStartTime and WorkingHoursEndTime were having invalid time set. Changing these values to correct time settings can be done using the Set-MailboxCalendarConfiguration. For example:
Set-MailboxCalendarConfiguration - identity "affected user" -WorkingHoursStartTime 08:00:00
Set-MailboxCalendarConfiguration -Identity "affected user" -WorkingHoursEndTime 17:00:00
After changing these values to regular working hours, the magical disappearance of the meeting room(s) has ended when this user was also scheduled.

There is also published support article from Microsoft about this phenomenon on https://support.microsoft.com/en-ca/help/2852702/a-room-or-room-list-disappears-in-scheduling-assistant . It's stated that Exchange online is affected, but in my case I have experienced with Exchange on premise.

Happy Scheduling :)

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