Random delays from 10-15 minutes to hours are now "normal" for Polo. In the last 48 hours it's happened for me with STEEM, SBD, and NAV. Others have had ETH in "pending" limbo for hours. I'm using Bittrex more and more... at least they bother to flag wallets that are delayed.
RE: Is this normal to have Poloniex deposits stuck in limbo all day?