I’d seen people report a “IoC cannons won’t shoot” bug, but never experienced it myself until the last game.
Was the Horde southwest tower, closest cannon to the west gate. Cannon was working just fine until it had been destroyed and I repaired it. After getting back in, pushing 1 and 2 did nothing, nor did clicking the buttons. Exiting the cannon and reloading UI did not help, nor did returning to the cannon later in the match after I had died. I was perma on the “nope” list for shooting it.