What's in your bitcoin.conf ?
minrelaytxfee=0.0001500
blockmaxsize=919899
blockprioritysize=44308
limitfreerelay=6
I have found valid,
tx containing blocks in the past..
Additionally, logs from bitcoind. The time shows in UTC here, would that matter?
2016-04-15 03:20:49 CreateNewBlock(): total size 919823 txs: 1748 fees: 35821561 sigops 3928
2016-04-15 03:21:04 CreateNewBlock(): total size 919890 txs: 1742 fees: 36105460 sigops 3945
2016-04-15 03:21:13 UpdateTip: new best=000000000000000003828fbc61ad281aa2e298ed4a299abf36209a4725d51930 height=407355 log2_work=84.488361 tx=122495866 date=2016-04-15 03:20:49 progress=1.000000 cache=287.3MiB(138792tx)
You are sure it's your miner that found the block (I'm not familiar with if that message says you found the block or someone else did)?
There's something screwy going on because your bitcoind is offering transaction based work just before you found the block of 910k Perhaps for whatever reason your p2pool client kept building empty block work indefinitely after the previous block through some bug. Is your p2pool code modified in any way?