The following does not respond to your exact question; but may be helpful. Unfortunately it is too lat to help with the problem you have now.
I make the first transfer to a wallet I hold (warm or cold) where I get to control the private key. Then, I do the second transfer from my wallet. That way, if anything is lost in the second transfer I still control the amount because I hold the private key.
Good luck.
RE: Poloniex problems