Ran into a glitch where companions suddenly turned hostile. Was during the Cabot mission in the insane asylum (ironically). Had Cait, Curie & Piper in tow when in one furious firefight with raiders, Cait & Piper started shooting at me, Curie & Cabot. I'm not certain but it sure seemed that the extra slotted companions have unstable AI behavior. Pre-GECK mods obviously does have some shortcomings.