The chair has started to “wobble” when sitting in it. When it first started it was just a slight - lean on left arm rest, the chair would tilt a little to the left.
It has progressed to: backwards, forwards and left side, even a slight weight shift and it will tilt several degrees.
All screws are as tight as I can get without a drill, all parts are in visibly “like new” condition.

The “wobble”/shift can be performed by hand as well with no weight on the chair. The visible shift is somewhere between the chair mount and the center gas cylinder but have been unable to find any fix