It is normal.  It means there is no work in the network for miners. Unlike Bitcoin and other Altcoins, Kryptohash doesn't send miners "dummy" work if there are no transactions in the network.  It would be a total waste of electricity since those dummy blocks will never be accepted by the network.

Nonce-pool had a script that was monitoring the network and then sending few cents to its own wallet if the script detected that the network had no work to do.  This kept the network and the pool busy.

I'm looking into doing a similar script.