Good afternoon and thank you for posting on the Final Fantasy XIV Technical Support Forums.

When did this start happening? Do you recall anything updating/changing on your PC that coincides with this?

Overlays are one of the things that can interfere with the game. If you have any overlays active (Geforce Experience, Steam Overlay, etc.) try disabling it.

You may also want to try a clean boot. Simply open the task manager and select the 'Start up' tab. Disable everything here and restart the PC. This will make sure that no background processes are interfering with the game.

We hope we can be of assistance in helping you enjoy the exciting world of Final Fantasy XIV!