It works fine, (at least for now) and the payments turn up quite fast on cryptopia.
Make sure you have, the wallet_adress.id_string (provided by cryptopia) in the miner configuration.
On a side note, watch out for those pesky network fees of BTC which are on the rise again and cryptopia wants 0.002btc for each TX.....
It worked fine for me as well on Saturday. Payment showed up on Cryptopia within 5 minutes. But this morning, payment confirmed on Nanopool, but 1 hour and 30 minutes counting, nothing on Cryptopia

I'm afraid if I submit a ticket, they'll just tell me I shouldn't be mining to my Cryptopia account, but clearly it should work... 12 of the top 15 miners on the ETN Nanopool are mining to Cryptopia.