Destroyers not keeping station in formation

[hellfish6]

I was playing JCR's nice little ASW scenario. I adjusted the stations when the scenario started, and afterwards the two escorting destroyers just took off on their own at cruising speed. They'd respond to direction changes, but never made an attempt to return to station even after trying to set the stations several times.

Not sure if it's an error on my part, as this is the first time I can remember adjusting the formation in a scenario that someone else made, or if something under the hood is wonky.

Save attached.