Why do I suddenly stop in the middle of shooting someone to toss a grenade? This just started happening a couple of days ago. My Max will randomly go in and out of lockdown as well. Haven't changed any settings on mouse or keyboard.
Haven't had that happen. I do know if you keybind F key (default overshield, throw ammo, etc.) as infantry onto mouse, it refuses to trigger reliably. Maybe check you haven't bound these to some other peripheral PC device. Also there's a new bug related to Maxes where after respawning your weapons are either temporarily or permanently jammed, if the latter no ability works until a restart. This happened randomly before, but now I find it be triggered with max use.
Does this still occur when remove all grenades from your character after your next respawn? Just curious to see if you still see that nade tossing motion when you have no nades. Do you have your Mouse middle wheel setup to scroll through your weapons?