Calendar Reminder Pop-up can't be disabled

Calendar
1

eM Client on MacOS here. Version 10.4.4867. Concerns Exchange accounts

I want to totally disable the calendar reminders pop-up. I manage a large team and I get pop-up’s for all their calendar events. I know how to disable that in the account properties, but every time I reopen someone calendar (I don’t have them all enabled by default), the “show reminders” in properties is enabled automatically. I keep turning this off but it is bore.

Disabling the pop-up in eM Client settings under Notifications is not possible “Sorry, but this option is not available for this item”.

How do I get rid of these pop-ups once and for all?

2

Just now I again got a Reminder pop-up with:

  1. An event in 5 minutes from someone else’s calendar that I did not show and had “Show reminders” disabled already before. When I clicked the event I got an “this event has been removed and this window will close” error message. I then revisited this calendar’s properties and saw “show reminders” was enabled again. But not by me. Show calendar was not;
  2. An event from an iCloud calendar of 1 day and 6 hours ago. I have been working on my laptop with eM Client active for hours already. This was the first reminder pop-up of the day.

Is the Reminders pop-up broken?