Mothballed and Reserve Ships getting Mined/Torpedoed

[sagaren]

I've noticed across several playthroughs that Mothballed and reserve ships are often torpedoed and mined, being damaged or even sunk in the events windows during wartime. I imagine this is bug as I can't see how Mothballed ships at least are getting mined and torpedoed tied up in harbor somewhere.

[dorn]

I think that these ships being mined is strange but torpedoed can be possible.
Look at history and submarines ability to torpedo ships in harbour. Everything is about quality of antisubmarine means. So if it is one or two times per game I would think it is OK as your antisubmarine defences in harbour could understimate enemy.