shared google calendars not showing up on MacBook Pro Apple calendar but are on iphone and ipad

Same problem: In the last 24 hours, google calendars of mine and of my employees have all disappeared from OSX Calendar on my iMac (yesterday) and on my MacBook Air (today). Interestingly, *some* recurring events still seem to show up, but that's it.

No problems (yet) on my iPhone XS, which still seems to show everything fine.

Some older threads from 2018 seem to reference a similar problem happening and it having something to do with a 10,000 item limit in the API connecting google to OSX Calendar? Might be related, might not be. Also, in my case, this is a Google for Business account which usually doesn't have annoying limitations like that.

Have tried quitting, restarting, updating system software, you name it, and no change.

Just noticed it today (Aug 23). Tried Refresh, tried, unchecking and re-checking the box, no dice.

I've went to the Google Calendar forum and there are over 100 people reporting the issue there as well.

Solution!

Step 1. With Calendar app closed, I deleted the 3 Calendar cache files in User/Library/Calendars and then there are 3 files that start with the name "Calendar Cache"

Step 2. After reopening Calendar, historic calendars were not showing up despite still being saved in the Library files. Default OSX Calendars were there ("Home" + "Work"). I deleted those.

Step 3. Calendar Menu: Accounts (or go from System Preferences) and unchecked and then rechecked the "Calendars" checkbox for each account that I use calendars from (in my case, my Google for Business account and my iCloud account).

Voila, everything back to normal.

A couple hours later, I was at my work computer and didn't even need to do the same process there because it had fixed itself. Not sure if that's because I had done the above process on my laptop, or if Google and Apple fixed the original problem overall.