Logitech optical mouse keeps jumping a few pixels when I click the left button

[Participant]

Has anyone experienced this? Brand new fresh Duracell batteries, clean optical sensor...for some reason the mouse cursor creeps up sometimes mainly when I click a button on it.

Bit stuck as I like the mouse but it's a very annoying habit it's gotten into!

 

[Participant]

Just changed the mousemat and it seems to have stopped doing it. Strange though as I've been using that mouse mat for a few weeks.