Sinkings not being credited.

[Mouftic]

What's going on...

I attacked a convoy with a nice Bogue class right in the middle.

I send 2 torpedoes for him both impact (one mid forward one mid aft), does not sink.
I send 2 torpedoes for a large merchant both impact and sinks right away.
I send my aft torpedo for a large cargo (mid forward), does not sink.

There are 8 escorts for the convoy. I start zigziging in the convoy at periscope depth to avoid them (i'm getting rather good at this, don't know if it's realistic, but none the less) until I get a reload to finish the unsinked targets.

The Bogue class get stationnary and lists pretty hard to port side. The cargo just keeps going unnafected. All torpedoes were magnetic under the keels.

After I get my reload I fire another at the Bogue and the cargo, another hit but takes about 4 to 5 minutes game time to sink.

My crew goes "yeah", she's going down message, red sink icons appear on the map. I look at the captain's log, no sinking recorded on the Bogue or the Cargo.

I read in a post somewhere that if the weather was rough you could get "robbed" of sinkings, but not the case here, it's a very calm see.

Any other explanations?