I ended a void fissure mission with the primary weapon unlimited ammo buff on phantasma prime. I was firing when it ended, with Yareli while riding Merulina.
Now nothing that uses the fire button (M1) causes the expected interaction in game, except the slow down function of the landing craft in loading screens.
Sometimes I can get the primary or secondary to autofire but it's not clear what conditions cause this, seems to be switching between merulina or other boards and foot. When this happens it will not stop firing until I switch to melee, after which I am locked out of the fire button again.
This condition is persistent through remapping of controls, changing loadouts/warframes (including removing all weapons but melee) and logging out and in, and validating the game cache. I am currently still unable to use the fire button for any function, ex shooting, mining, conservation rifle.