UPDATE - I just checked on the rigs and both miners were reporting they were hashing away just fine but the pool said bminer was offline. After restarting bminer the pool shows it back online again but there is a steep dip and rebound in the hashrate graph; earnings were affected as well, with dstm now at 0.0374 ZEN and bminer 0.0356 ZEN, so this wasn't a pool issue. I can't think of a worse failure mode for a miner, really - it was still drawing a huge amount of power and appearing to work, but not actually doing anything useful.
Yeah, I had this issue yesterday. Bminer was still mining full speed locked at some task, while the dashboard showed I was offline. Restarted the miner and it's been going strong for 24 hours now. The only problem is that the rewards I'm getting from the btg supernova pool are miniscule. Like 3.5 times lower than what the WTM site estimates.