Hi there,
The issue seems to be with your keyboard, especially if you are using a laptop. Sometimes the electrical matrix underneath gets damaged (by soda or other things accidentally dropped on the keyboard, strong/repeated physical actions, etc) and pressing one key cause 2 or more electrical contacts to be created, instead of one.
If you are using a multimedia keyboard, try reinstalling the drivers.
I personally experienced this issue with older remote access software, which caused all my keys to act as hotkeys, forcing me to reboot to restore the keyboard to its normal functioning.