sentinel advance II tracking issue

[Walker998]

back when it was new one of the flaws was the tracking is sometimes unreliable which i have noticed with very occasionally it's very hard to move in one axis while the other is fine

but now after it happened very recently tracking feels less fluent than it is with the mouse usually,

it has more trouble (as in slower and clunkier) going from the bottom-left to the top-right and vice-versa, and perhaps a little up and down but can 

anyone know if it's a sign of wear since i have had it for about 3 or so years, or something else?

i have really been interested in getting a mionix castor and if it is a sign of wear looks like i will be getting one sooner