Are we still having sync issues? I have a lot of "Mined" transactions from a few days ago that have 0 confirmations. I have updated to the new wallet and it was up to date, but still the older mined transactions are not getting any confirmations. All the new ones are fine.
EDIT: It may have something to do with the wallet. When I look at the sync message it has 12419 download of 12478 blocks.. but the last block was only 12419.. Does that help?
That's common with PoS. The fact that you minted them does not secure their entrance to the blockchain. Some other wallet with "heavier" coins won. It's a competition between wallets.
Your coins are not lost though, your client will keep trying till you get your stake included in the blockchain.
Another common issue with PoS is exactly that. When you have too many blocks that are minted one after another and they fail to enter the blockchain, your wallet might get "banned" by the other wallets, because it looks like your wallet is trying to inject lower diff blocks and that behavior is like trying to "hack" your way into getting more coins.
When that happens, you get sync issues. The best thing to do is just (always do that) copy your wallet.dat file somewhere (after you close your client) and then re-open it (if you can wait for a couple of hours, the better).
That way the blockchain would be ahead of your wallet, your wallet would understand that your blocks can't be included and stop broadcasting them to other wallets (thus avoiding getting banned again) and if you still have issues syncing, just "repairwallet" as described before.
I hope this helps to better understand how the PoS works and why things happen the way they do.