Info missing here: vanilla game?

Which ship?

What caused the damage?

Vanilla game.

I tested[vk.com] all CL and CA that had torpedoes. Didn't test DD.

In Custom Battle I fired the gun until the compartment frame turned black. Sometimes I let the fire that started do the job.

Tested with DD Fubuki[pastebin.com]. Same result.

Markus, I seem to have found another bug during testing. Have you already launched the save I posted above? Try to reproduce this disposition.

Custom Battle. Play Side – RED (Japan). One RED Task Force with couple of ships. Then save game and try load it from Single Battle.

Update.
Not only Destroyed torpedo tubes.
ANY torpedo tubes whose maxTorps has reached zero.

This effect can be observed even in the Museum.

But we can deselect functioning torpedo tubes with no more torpedoes. And fire from the remaining torpedo tubes those that still have torpedoes. And Destroyed torpedo tubes cannot be deselected, so they block the ability to fire from all torpedo tubes with higher indexes.

FireWeapon in WeaponTorpedoTube works at least up to the point where it sends TorpedoFire message to log. Further, before calling SpawnTorpedo, there is an error somewhere. It is literally two lines: assigning the variable num2 and checking it.