I regularly get stuck on mountable machine guns (not the EV gun & not Bushwacker turrets; the pre-existing guns that are fixed+stationary on the map). The issue frequently occurs while playing as Sparks (I have not yet experienced it with any other characters, but I play ~90% of the time as Sparks and 10% as Aura- so that could be a playtime bias).
When I am on the turret & press my button to throw a medkit, it’ll take me out of the turret-vew, throw the medkit, and then if I get back on the turret I’ll get stuck to it: I can’t fire and I can’t exit (though I can still pan around).
This doesn’t happen every time I throw a medkit from turret-view, but seems to be repeatable about 50% of the time. Once I’m stuck to a turret I have to hit K to suicide, and for the rest of the match I tend to get restuck if I try getting on the turret again. Only once did it seem to reset and let me use it normally, after 1-2 minutes had passed since my last attempt.