Reminders app doesn't mark items as complete until restart on Mac

I check off a Reminder and it sits there and sulks. It can be an instance of a daily repeating reminder or a long-standing dated reminder or a reminder from earlier in the day, or a reminder I set up on my iPhone with Siri. I can look back at it, with firm intent, but it doesn't go away - it just sits there until I quit Reminders. When I restart Reminders it's gone (marked as complete).

M4 Macbook Air running Tahoe 26.0.1

What to do? How about the Apple Programming team contacting Haha Interactive for advice? Their program uses the same database, I believe, but the glitch I describe above doesn't occur in their GUI.

There's clearly a better approach available than the one taken by the Apple programming team!

[Re-Titled by Moderator]

Original Title: Reminders is poorly programmed!