I also want to mention that the new RC is out:
https://github.com/NebulousLabs/Sia/releases/tag/v0.5.2-rc30.5.2-rc3 features a single change - some miners were reporting errors when mining, and I believe it was due to the way that the miner was calculating the height. I've added some extra logging, so we'll have more information even if it does not seem like I've fixed the problem, though I believe that the fix is now in place.