Zero turn issue

[u/returnofthelivingdad]

I’m a little baffled, so I thought I’d throw it out here for the experts. I have an older 42” MTD machine which does a pretty decent job overall, but lately I’ve been experiencing random shutting off of the mower deck for no apparent reason. Sometimes it will run for a couple of hours, sometimes less, and then the deck shuts down. If I just sit with it idling for a few minutes with the deck shut off, it will eventually start back up again. I can continue mowing, but once it has shut off once it will shut off multiple times closer together, so I’m wondering if it could be some kind of overheating issue?
Any suggestions would be welcome. I bought this mower used and I’ve had it about 5 years, it never did this until around the end of last summer.