@join Thanks for that!
Been playing with Reaction Time and Reaction Time Octaves and I'm getting the feeling that Reaction Time Octaves only comes in to play when I move from one thumb pad to another. My issue seems to occur mostly when I lift my thumb (and simultaneously change fingering on the front side).
In the fingering I'm using, lifting the thumb goes up an octave ... but this seems to use the Reaction Time delay and not the Reaction Time Octaves delay. Is that correct??
One solution is to introduce a very slight articulation to interrupt the airflow. I've started doing this subconsciously and this reduces artifacts (pops and beeps) substantially.