Mouse Ping Bug

So recently I have been having a strange bug with pinging while in game. I have my keybindings set so that pressing the left Alt key and then clicking is how I use an alert ping (i.e. "on my way", "enemy missing" etc.). I recently got a new PC and set all of my keybindings, and the pinging sometimes bugs out and I can't ping at all. My mouse cursor will be the image of either the default pointing finger, the sword (the one that appears normally while hovering over an enemy) or the target symbol while placing a ward, and it will be stuck on that image and does not change no matter what I move my cursor over (it is supposed to change between each of those). It will not allow me to ping, and I cannot left click on anything while this is happening. This includes any enemy champions, minions, or structures to see stats and items, and even the mini map in the bottom right corner. If I am top lane with teleport while the bug occurs, I literally have to scroll all the way down the map to see what's going on, because I can't left click on the mini map, and I can't ping my teammates to let them know if I am coming or to back off. This is very frustrating in a game. The bug does not happen consistently. Sometimes it doesn't happen at all in a game, but sometimes it happens over and over in a single game. The games where it does happen, it will sometimes go back to normal and then bug out again. I have no idea what is causing it, or why it goes away. It seems to be very random. I have had these same keybindings on my laptop for years before getting this new PC, so I have no idea why this is happening. I have tried changing my keybindings while it was bugging out in a game, and it did not fix it. Does anyone know what is happening?