Not sure if it's of any help, but I recently swapped my turbo.
Put it all back together including intake, disconnected the CAS and cranked a few times (to build some oil pressure - it's debateable whether this is needed or not, but nonetheless I did it), then reconnected the CAS and started it up.
Wouldn't idle properly at all due to loose intercooler hose, so I fixed that up and started her up again.
Idled smoothly but shot up to 2.5k and slowwwly dropped over about 5 minutes to normal cold start idle.
Like I said, not sure if there's anything in what I did, that's related to what you did, but hey there's my info - hope it helps.