Solving A Motor jumping issue (MM driver and Ard)

I enjoy reading full and complete comments @OZHEAT. Thank you for taking the time to write them. I had started with 10 k pots and moved to 25k pots to try and help solve the issue. I kow very little about electronics so I can only comment on what I notice and not why it is doing it. But one thing I did notice was that the 25k only would use its first half of the 170 degree rotation.
Regardless I did end up building a completely separate set up. using 10k pots. It all seemed to work great, So i brought over the Ard and Hummer MM I was using at first and plugged it in. Hoping the MM was what was causing it. But they worked well too, so back they whenm to the chair. And then I switched the chairs pots to 10k but (and I think this is the thing as dumb as it sounds or as simple) while changing the pots and setting them up I forgot the power on and Just wiggling the wires on the pot made the motor jump. It was kinda like when you have old head phones and the wires get tired and the connection goes in and out. I think all this time I was chasing a bad soldering job. I rebuilt 2 new pots and changed the code pot ports from a4 and a5 to a3 and a2 because they had seen no abuse yet. And no more jumping.

good news

One other thing I had switched was the power wires on the motor itself . I moved to a slower speed and consequently had got a quicker brake.

@james wheeler
Can you test something for me?
With the seat powered up and holding a stable position, can you push and pull on the seat.
Does it kick back at you at any point?
Cheers Andy

@OZHEAT I tested the seated rigidness and its stronge like ox. I ca sit on it even with out it moving.