I can't really check for reference at the moment in game, but that's also another good point. Does the Cannon include the K'Tinga as a valid ship for it to be slotted on?
If you're a commander, and the cannon is listing the ship on it, then it is certainly not working as intended and definitely a bug, as all the conditions for equipping it are met.
So when the game servers come up, should take a look to double check to see that the K'Tinga is allowed to equip that specific weapon in the listing.
Good point, the cannon had the Bop, Raptor and Battle Cruiser listed on it. It did not list K't'inga by name but I assume the Battle Cruiser fits the description. I will compare the Mk IV and Mk VI descriptions as soon as the server is up.