Calendar Event Travel Time bug

I have done some troubleshooting for why I am unable to add a travel time to an event on my calendar.

I am subscribed to my daughter's swim team's shared Google calendar which uses "all day events" for swim meets (because of the structure of swim meet sessions for different age groups it's the only simple way to add an event to the team calendar).

When I try to create an event that has the same address on the same day as that all day event, Calendar won't let me use the travel time feature it reverts to a manual time only mode.

I know this is the issue because if I unsubscribe from the shared google calendar in Accounts and try to create the same iCloud event I am able to add a travel time for it. However, as soon as I re-subscribe to the shared Google Calendar the travel time reverts to a manual time — yet shows the little car icon as if it were an actual Time To Leave time.

I have tried to uncheck "This Calendar Affects Availability" in the shared Google Calendar "Get Info" pane on my Mac, but it keeps getting reverted to checked. Worse yet, it seems there is a battle between my macOS Calendar and my iOS Calendar. If I turn it OFF on one, it gets turned ON on the other.

So far I have removed all Calendars from my Mac and Calendar accounts, signed out of my iCloud account, rebooted. I haven't done this yet on my iPhone.

Real Issue:

I am thinking the issue is that I can't toggle "Events Affect Availability" OFF on my iPhone or iMac without it being automatically toggled back ON. If we can tackle that question first and see if that fixes it.