For several weeks now mouse buttons do not work properly, e.g. back/forward side-button does not work in firefox or stops working after some time. Killing your software and restarting it fixes this issue, so it's definetely a software issue! In addition, the software takes quite some time to 'configure' my device upon startup, I can hardly believe this behavior is to be expected. My mouse (MX master 3) has been working fine for years, the issue just occured recently. For sure, this is an issue with your software. Please fix this, or my next mouse will not be a logitech-mouse :-/