I'm having an odd experience with my Mate 20 Pro and Google Calendar. Occasionally, the calendar of my primary Google account will simply just gone missing, and a message will prompt showing "Calendar are hidden" when I launched Google Calendar App. Kindly refer to the attached for the screenshot of the error message below.
Diving into the app's setting page, I noticed that the Gmail account of my missing calendar got delisted, but the same gmail account is still exist in my phone's "Google service" setting without affecting my Contacts, Drive, Chrome, and Gmail, etc.
FYI, the switch to sync Google Calendar is still remain toggled 'On' when this problem 'missing calendar' occurs.
What's even more bizarre is that, my calendar will return by itself after a few hours without my intervention.
Oh, one more thing, using the stock calendar app to sync my Google Calendar doesn't seems to help too. When I'm getting a blank calendar at Google Calendar the stock calendar app gives me empty calendar too.
Also, this issue seems to affect my Mate 20 Pro only, as the same Google Calendar are not missing from my iPad, iPhone, Macs & Samsung S8. Thus, I'm pretty sure I can rule out Google's fault.
I wonder does anyone of you here are experiencing the same problem as I'm having here? If you did, what did you do to address it?