[2019] Seemingly random item switches most often during combat

Normally the reports are that it doesn’t switch when players want it to, rather than random switching of it’s own accord.

I do suspect this to be a hardware issue. As Ricordis says, any particulars about your set up? Other peripherals plugged in? Anything that might interact with your mouse? Does your keyboard have a touchpad perhaps or a scroll wheel of it’s own? Anything at all?