Hmm, two of my nodes went down at the same time. Other nodes were unaffected.
2017-09-13 22:40:50 ProcessNewBlock : ACCEPTED
2017-09-13 22:40:50 ERROR: CheckProofOfWork(1): BibleHash does not meet POW level, prevheight 7491.000000 pindexPrev 64$2017-09-13 22:40:50 ReadBlockFromDisk: Errors in block header at CBlockDiskPos(nFile=0, nPos=3269787)*** Failed to read$2017-09-13 22:40:50 Error: Error: A fatal internal error occurred, see debug.log for details
2017-09-13 22:40:50 ERROR: ProcessNewBlock: ActivateBestChain failed
2017-09-13 22:40:50 tor: Thread interrupt
2017-09-13 22:40:50 msghand thread interrupt
2017-09-13 22:40:50 torcontrol thread exit
2017-09-13 22:40:50 scheduler thread interrupt
2017-09-13 22:40:50 addcon thread interrupt
2017-09-13 22:40:50 opencon thread interrupt
2017-09-13 22:40:50 mnbcon thread interrupt
2017-09-13 22:40:50 net thread interrupt
2017-09-13 22:40:50 PrepareShutdown: In progress...
2017-09-13 22:40:50 StopNode()
2017-09-13 22:40:50 Verifying mncache.dat format...
2017-09-13 22:40:50 Loaded info from mncache.dat 0ms
2017-09-13 22:40:50 Masternodes: 0, peers who asked us for Masternode list: 0, peers we asked for Masternode list:$
2017-09-13 22:40:50 Writting info to mncache.dat...
2017-09-13 22:40:50 Written info to mncache.dat 1ms
2017-09-13 22:40:50 Masternodes: 0, peers who asked us for Masternode list: 0, peers we asked for Masternode list:$2017-09-13 22:40:50 mncache.dat dump finished 1ms
2017-09-13 22:40:50 Verifying mnpayments.dat format...
2017-09-13 22:40:50 Loaded info from mnpayments.dat 0ms
2017-09-13 22:40:50 Votes: 0, Blocks: 0
2017-09-13 22:40:50 Writting info to mnpayments.dat...
2017-09-13 22:40:50 Written info to mnpayments.dat 1ms
2017-09-13 22:40:50 Votes: 0, Blocks: 0
2017-09-13 22:40:50 mnpayments.dat dump finished 1ms
2017-09-13 22:40:50 Verifying governance.dat format...
2017-09-13 22:40:50 Loaded info from governance.dat 0ms
2017-09-13 22:40:50 Governance Objects: 0 (Proposals: 0, Triggers: 0, Watchdogs: 0/0, Other: 0; Seen: 0), Votes: 0
2017-09-13 22:40:50 Writting info to governance.dat...
2017-09-13 22:40:50 Written info to governance.dat 2ms
2017-09-13 22:40:50 Governance Objects: 0 (Proposals: 0, Triggers: 0, Watchdogs: 0/0, Other: 0; Seen: 0), Votes: 0
2017-09-13 22:40:50 governance.dat dump finished 3ms
2017-09-13 22:40:50 Verifying netfulfilled.dat format...
2017-09-13 22:40:50 Loaded info from netfulfilled.dat 0ms
2017-09-13 22:40:50 Nodes with fulfilled requests: 0
2017-09-13 22:40:50 Writting info to netfulfilled.dat...
2017-09-13 22:40:50 Written info to netfulfilled.dat 1ms
2017-09-13 22:40:50 Nodes with fulfilled requests: 0
2017-09-13 22:40:50 netfulfilled.dat dump finished 1ms
2017-09-13 22:40:50
BiblepayMiner -- terminated
2017-09-13 22:40:50
BiblepayMiner -- terminated
2017-09-13 22:40:50
BiblepayMiner -- terminated
2017-09-13 22:40:50 Shutdown: done
2017-09-13 22:45:05
I was able to just restart biblepayd with no apparent issues and they're fully synced with the network again.