There is nothing wrong with the network. Miners are just not paying masternode rewards. They can do that because masternode payment enforcement is not yet enabled. It will be enabled by us in the next days.
And what is the reason for that? There is no incentive for the early MNs...
Because when we started there were no masternodes. So we cannot enforce something that does not happen. Now that we have enough masternodes we can enable it. Its just how it technically works.