Boarding bug

Using BM 1.10 (although this probably occurs in stock too) I noticed strange behaviour in a boarding battle, so i created a base with around 20-30 defense stations, now if a sigle one of my boarding ships (4 BP on each) attacked the station and its crew suffered no damage at all, however if two ships attacked (making the total 8 BP's) all of the ships defense station components became instantly destroyed and the crew began reducing.