I've been playing through the HL2 campaign - because why not - I'm up to the canals and I decided to weld the M60 turret to the top of the airboat for a little more firepower - with some spread ofc so it's not as powerful.

However, when doing so, after a while of having it mounted the console eventually starts getting spammed with this error:

[Towers & Turrets] lua/entities/tnt_turret_base/init.lua:234: attempt to index field 'TurningLoop' (a nil value)
1. UpdateTarget - lua/entities/tnt_turret_base/init.lua:234
2. TurningTurret - lua/entities/tnt_turret_base/init.lua:271
3. unknown - lua/entities/tnt_turret_base/init.lua:224

I haven't tried removing the turret yet to see if it'll get rid of the error, but I'm pretty sure it would anyway. It seems as though the turret doesn't like being mounted.

EDIT:
Ok, so I'm up to Eli's Lab and I haven't spawned any turrets at all yet. I'm still getting the error, though.