Slitherine

The transport moved north and bumped into the US sub.
Neither of the Japanese destroyers are able to attack the sub.
Using the sonar doesn't help, still unable to attack.

This looks like a bug unless I've missed something.
v2.2.5

Thanks for the save, there was indeed a bug in the logic (sonar only being able to attack if the sub was not idle in its previous turn - which only makes sense if the sub isn't already revealed!)