It seems more likely to be third-party software doing weird stuff with your input, then. Game settings don’t affect jumping movements. If it only affects certain software, then it isn’t hardware related either (though it’s a good idea to check your mouse sensor for any debris like hair or salt or w/e might get in there).

Sometimes software intended to enhance gaming can interfere with all sorts of strange and seemingly inrelated things, even software packaged with graphics cards.

Mouse settings may also be relevant; I had problems with my camera sensitivity randomly becoming extremely high in ESO, a problem that later affected WoW as well. Turned out to be a side-effect of a high mouse polling rate. If you mouse is advanced enough to have its own settings and configurations, they may not be converting well to Overwatch.

Something especially curious to note is that the pattern is the same… always to the top-left, at a low angle. Games like Overwatch that use the mouse for aiming technically hide the cursor and repeatedly ‘reset’ its position to the centre. Could another window or application maybe be trying to move the cursor to the top-left and impacting your game?