Water spitting out shower

For the past few days the water has been spitting or sputtering for about 2-3 seconds after the shower has been on for about 1-2 minutes. It only does this once during the shower. Any ideas what is causing it or how to get it to stop? Water is from city supply and shower is seperate from tub with single lever valve. No recent work done on plumbing system.

I'm not a pro, but was wondering if you were on a well or municipal water? If a well, could it be air getting into the system when the pump turns on? Maybe the check valve leaks a little and the system pumps a little air. Could be totally wrong!

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This is not a common complaint. What kind of shower valve do you have and do you have an expansion tank? Does the spitting occur without the shower head on? Is the diverter on the spout or in the valve?