Hi @kjw ,
have you checked all the Phone apps' settings? It seems that there is an option to play a tone when the call connects. You can deactivate this from the Phone app> Menu (3 dots top right)> Settings> Call alerts> Play tone when call connects> Turn Off if On.
That was the first thing I checked. The toggle is and always had been in the off position, but I get the tones anyway. This just started about 2 months ago and I'm stumped as to why.