I'm having the exact same issue and had a thread about it as well. No responses yet, maybe we'll get attention to this and someone can help. I have the exact same number of blocks every time it happens, and it is like 215604 blocks, but it NEVER downloads them. Restart wallet and PRESTO! issue goes away.
I read in another thread that it was just cosmetic, but as I have just started with cryptocurrency mining and MNC is the coin I chose.. I just want to make sure that I am not crazy and things are still "working". If I restart the wallet, it works fine. I just don't want this to interfere throughout the day while I'm sleeping and such. Thanks for your help in advance!