Thunderbird 140.9.1esr on Windows 11 (64-bit) - Home Calendar event reminders not working i.e. the reminder is not being generated.

I can setup the Calendar event, save it and see it in my Home Calendar along with the little bell icon in the top right hand corner which tells me the Calendar is aware of the notification request. I generally add a reminder for the Calendar event but just noticed that no actual reminders are being generated.