I notice my cgminer does get stuck sometimes and work restarts. Seems to be early on that it all might be trying to adjust.
I had it freeze for a good hour twice, the speed up top 5s 1m, 5m would slowly drop, but the miner specific hash would freeze. , no change, I even gave it a good long while watching it once. This never happened before adding a key to the wallet, and immediately after it started. I'm going to set a wallet up on another system and see if it happens.