This can somtimes show up when you are playing games that require longclicking of both mouse buttons. (I found this when playing the heavyweapons in tf2)
Use xinput list
to find your device id
Then use xinpit list-props <ID>
to find the relevent property name to set.
You can then set the property to 0 to disable it ether by using the device and property name like so
xinput --set-prop 'Kingsis Peripherals ZOWIE Gaming mouse' 'libinput Drag Lock Buttons' 0
or just using the id numbers
xinput set-prop 9 296 0
More info in the arch wiki