No, this is definitely not normal. Deposit times can vary by cryptocurrency, but I've never had one take more than an hour and typically they are faster than that. However I've never tried depositing Steem or SBD with them. Could be a momentary Steem network issue. I'd open a support ticket with them as @claudia suggests. But try not to worry, Poloniex is usually very reliable and I'm sure it'll get sorted out eventually.