Not really, just market in general is down by a lot.
COSS did lose a lot more than most coins, it would've been probably the worst performing serious coin if it wasn't for the whole Bitconnect scam which made people dump like crazy, it lost 95% of its value, however, COSS is performing like a lot of pump and dump shitcoins, losing 75% of its value in a week. Yes, there was a massive correction, but most coins didn't lose more than 40%, and COSS lost nearly twice that much.
However COSS is not a shitcoin and has developers who will definitely keep improving the exchange. It's in their best interest to try and make it as one of the top exchanges. It can dump and dump and dump but it doesn't change the fact that it's one of the coins to keep an eye on in 2018.