That was one of the problems I had with the Jericho tenor I briefly owned (and returned) - I got a nasty squawk doing the transition to D2. It may well have involved a short blast of the A overtone, I was never quite sure.
I was fairly sure it was a tendency of the sax, rather than me though. There were some mechanical problems involving key alignment, according to the repairman I showed it to.
I can see how closing the third finger slowly would be a cause of that though. I don't think I'm prone to that, but maybe the sax was - I guess a small leak on the G key, or something making it harder to close fully than the others - or a small leak in one of the palm keys, could probably cause the problem.
One thing I do have a tendency to do is catch the F palm key unintentionally, especially playing down to a G from any note that involves closing fingers on my left hand. I just have smaller than average hands, and shorter than average fingers, I guess. Some people like palm key risers - I'd prefer if they were lower.
That probably happens in both octaves but I notice it more playing the first octave G - it tends to overblow to a higher note / squawk, when I knock the palm F by accident.
I've actually bent that key towards me a little on my main alto, to stop that happening so much. I noticed I was doing it on my new C melody too, so that one might be next.
