"it happens quite infrequently. About every few days"

You consider such erratic behavior every few days to be infrequent?

The test I use for myself to decide what I can handle on my own versus what I need an expert for is this: Do I know what the cause of the problem is and do I know what steps are required and in what order will fix it? If yes, do it. If not, use the telephone.

well this might not be much help but when you are getting room temp air, is the compressor in outside condenser running? You should be able to tell just from listening. That might be a clue to your problem. if so, could be an electrical issue, I would follow up on my suggestion. Either way, I would call your dealer.

IMO

The start or run capacitor could be failing. This would cause the condenser not to start or continue running. It could also be just the condenser fan itself. Turn on the AC and go outside and listen to the condenser.

Thanks for the replies, except Elmer Fudd of course, whose comment is so stupid it makes me wonder why someone like that is on here. I'll do some more troubleshooting. Thanks again

Thanks Howdy. Hope you're having a good day. If you don't like my suggestion, then instead follow what tigerdunes said. He's a pro who works in the HVAC business.