I first noticed it around 0.8, but for some reason it seems like the only vehicle-mounted turrets I can get working are Flamethrowers. Plasma Guns will fire and consume ammo but do no damage, Machine Guns I can’t seem to load (They won’t except ammo from bins inside the vehicle, and ammo dropped on the turrets just falls through.) Fusion Guns I never figured out how to properly load sad to say.
Flamethrowers are wonderful, but they also have a horrible tendency to destroy my vehicle.