I've read a lot of forums and thought I was on to something with MemMaid. I downloaded the trial and the app seems to be conveniently laid out. I went to the Notification Queue to find the offending duplicate, dangling, expired, and invalid notifications. Selected each of those and deleted any that showed up (there were actually none since I had previously used the Quick Cleaner tab functions but I went through the motions anyway).
It did not help my problem of reminders not sounding.
I unchecked all the sound options, soft restarted, re-checked all the options, soft restarted again, ran MemMaid again but no luck.
Next idea? Hard restart?
Thank you for any help.
Mike