Completed Reminders Don't Delete
I have a couple thousand completed reminders across my lists because apparently the app doesn't have a setting to just delete completed apps after a certain amount of time. And when I try to get rid of them by clicking Clear Completed Reminders on iCloud.com from my PC, it doesn't update on my phone. But iCloud will keep reverting back to having the completed reminders. It seems to work for a list that only had 9 completed reminders, but it fails with the larger ones.
iPhone 8