Spontaneous death?!

[Snakeeyes]

Okay... this is my official WTF thread.

I am patrolling the east china sea. I am being buzzed occasionally by Nip aircraft. I took some hits but my damage control appear to have plugged every hole and patched everything back together. I'd say it was light to moderate damage.

I'm getting SD contacts and am at battle stations. I have the AA mount set with orders fire at will medium range. My best gunner is there.

I decide to take us to PD. We're there for roughly 60 seconds when I get a captain's worst call. PRESSURE HULL BREACH!!!

No way.

Boom. We bubble up and die.

WTF?!!!

I reload and check the hull for mines near us. Nothing. No aircraft. It's as if Horshima comes early on my boat.

There are no outward explosions or anything. Weird.

Experts... what happened to me?!!

My only though is that it was previous damage. It does not happen if I stay surfaced.