Tried this again yesterday after receiving your advice. Turns out they still shot at everything I targeted. Was on 'relax' and 'green alert', but they still opened fire. I'm guessing it's a bug but it's always done that from memory (for me at least). Will post in bug forum just so they know, now that I know it's not supposed to happen.
Statistics: Posted by Siridean — Wed May 25, 2016 1:07 pm