I have the latest version of the GECK but I can't seem to make him vulnerable in the game, even after deselecting all the tick boxes in his character profile. (He has two - one is SgtMontgomery and the other has a prefix like TEST or TEMP. I have tried changing both.)
I know how to make things like Liberty Prime vulnerable using the GECK, so the process is familiar to me. But doing the same process for Montgomery yields nothing.
Is this hard-coded into the game? Am I looking at the wrong data file?