I found this. I restarted and that didn't seem to improve things but googling indicated it may be a bluetooth issue (no idea how that works). In the end I noticed that Cisco Webex was taking a lot of resource despite not being used at all. I uninstalled it and ever since the Mouse issue has been resolved. No idea how or even if it is possible for other applications to interrupt with the mouse but it saeems to have cleared the issue for me. Running Chrome.
