Google was a nightmare for sociological reasons not dissimilar to what you describe.
Quick anecdote attempting to:
- colleague is a server-side engineer, highly sociable and communicative. They transfer to client side work on our team, get about a year experience
- new manager comes in but is quiet and absentee due to parental leave, about 6 months of a 9 month launch cycle
- manager assumes and communicates I'm de facto lead and should be getting people on the project
- colleague sees it more as a competition (residual from new manager coming in and me being de facto lead in between managers). new manager never spelled it out to everyone, so 6 months of hell ensue
- got to the point he went to manager's manager to complain regularly, eventually gets cut off and told to stop giving me a hard time because he's describing me helping him
- 2 weeks past ship deadline, with 2 weeks of work left, he repeatedly insists in a meeting that our work is in Binary A, but it's in Binary B, I let partner team deal with explaining it to him, I tried to avoid anything approaching conflict
- He consistently was a helpful contributor when he sat down and coded, but caused an infernal amount of racket between severe absenteeism and a sense of extreme alarmism when he was present and learning what was going on, because of the gaps like you explain (not knowing what you don't know)
- The bitter lesson I took away from all this was more or less that I did the right thing, I got them involved and was polite.and helpful with them, and there was nothing I could do to keep the abusive side of that from happening without causing a situation where it looked like I was uncharitable and failing at my duty to mentor.
- Didn't matter or help with my performance review. He kicked up enough noise to indicate smoke, so there must be fire, even if managers manager had enough at that one point.
- after launch, i spent the next 6 months carefully building a relationship with the other key team member via everyday things, lunch, cat pictures. That way, my relative formality was obviated, and they began being a good influence (i.e. being blunt with the trouble colleague when they were on another planet, rather than re-enforcing their alarmism)