"Repeat" feature stopped working

I have a Galaxy A53 5G. The "repeat" function has worked fine for several years, but a few weeks ago it stopped. When I mark a recurring task as completed, it does not create the same task at a future time. I have to undo completion and manually enter the new date for it. Deleting the task and recreating it doesn't help. The problem occurs with newer tasks and older ones. Occasionally it will start working briefly for a few times during a day, but most of the time it doesn't work at all.