I am running CGMiner 3.8.5 I also came home to one of my miners in that weird state (all lights off, zero hashing)... Rebooted the farm (with my 20 minute wait to cool down) and all was happy...
* I tested giving a miner 5 minutes of power and fans running to cool itself down enough to self test and it didn't...
* I also tested if the pi's could be turned on at the same time as the miners and would they complete their self test and start mining (even with work issued to them early) and that DID work so I can put the miners and the pi's on the same wifi controlled power switches if I want so that's good :-).
Like I mentioned before, if they are too hot to self test within 30 seconds, I have never seen them self test after that.
Thanks
On the bolded part, did you power cycle the unit when you did that? Also, what's the density of the installation, and were all the other units running? I can unplug mine from running full out and plug them back in immediately, and while it can take a minute to cool down they always come back up.