I did not put this topic in #bug-reports because I could not replicate it currently. If I should please let me know.
As I was battling the Minotaur, the Steam login screen popped up. Because I was holding and pressing buttons the password began typing itself as well. When I exited out of the login screen, my mouse stayed in the same position without me needing to hold down right-click. I was able to cast spells and use weapons while “shift lock.”
I tried to record the gameplay through Roblox, the shift lock canceled. This caused me to think, there must be a way to lock right-click by just pressing it once.