Stuck destroyer

In game 1122154 My French destroyer has been bombarding an enemy convoy at Florence Italy for some time now and yet the transport remains at 100% Every time I give the destroyer the attack command (even though the battle icon is still above it) I get the message "arriving in 41 seconds". I cannot disengage. The transport is not moving. I am pretty sure I have sunk transports before with a destroyer. Are you able to fix?