I also got this problem for serveral weeks now and it is extreme annoying, especially in competetiv modes. However it is not hardware related, because I tried a different mouse with the same result. It is also not GW2 related, because I have these problems in Battlefield V when zooming in with scopes with the right mouse button - also with the second mouse. So right now I think it might be Windows related. I don't want to reinstall my whole system :(