White box appears on the left side of the screen

I have a problem with my game in overwatch. Every time I press mouse 1 / left click
a small white box appears on the left side of my screen.

It only started happening recently and I don’t know why this white box appears every time I press left click/mouse 1/ primary fire.

This happens in any game mode I play, comp, quickplay, training ground.

This is not a bug.
You have turned on a setting.

Under Options, Video, nVidia Reflex
Turn off the “Flash indicator”.

This is used to test system input lag.

1 Like

there is no flash indicator setting under Nvidia reflex?