Knob or potentiometer might be defective.
Try some contact cleaner on that pot or maybe a software update to the latest version might calibrate or "fresh up" some things.
What I have noticed on one of my Timefactors is that there's something weird when using dual delays that even if all the "B" values are set to 0, there's still some "bleed-through" when using extreme settings on "A", like feedback at 99.
And another "issue" happened when I was trying the series delay trick, I set the feedback on both delays a little bit high, delay A time to 120ms and B time to 240ms, after a few repeats, B was no longer 2x the time of A, but it was only audible.
