You might want to try adjusting the air inlet. It's usually a ring that is held in place with a screw. Loosen the screw and then either rotate or slide the collar back and forth to admit a tad more air. It's a trial and error process to hit the right balance. There's undoubtedly a youtube video that demonstrates it.

^^^I agree with that esp if it’s a new install, but if it’s a sudden development I’d be checking to see that the burner head is perfectly clean, and everything is seated/assembled right. But yeah, something isn’t right. My understanding, a random yellow flicker is ok, but this is a problem.

This has been going on for a while.

Yes, should have said that-- first make sure all the jets are clean and open and everything is properly assembled. Compare it to other burners that burn clean, assuming they do.

OK, when there's no cooking pot on the burner, it seems to burn with an even, blue flame. Only when I have a cooking pot on it do I start to see it with a mixed yellow/blue flame. The other burners ae all burning a steady blue flame without a pot. I will have to try each of those with a pot when I cook next time.