In the "Summary -> Drawbacks" section, it mentions that Creepjoiners will become hostile if they receive friendly fire damage. (right after the bullet point list)
I just encountered a situation where a creepjoiner became hostile immediately after getting into a social fight with a refugee we were hosting (as part of a refugee quest he was a controllable pawn, even though he wasn't a permanent colonist).
I would just edit the page to add that social fights also make creepjoiners hostile, but I'm new to Anomoly (haven't played this game in a while now), so I don't know if this is completely accurate.
Is it the case that any damage the creepjoiner suffers from another controllable pawn causes them to be hostile? (for example, if you draft someone and punch the creepjoiner)? Maybe we should add this info to the page.