Ran a log last night and it looks like the client checks for a PoS block every 6 hours. =3
ComputeNextStakeModifier: prev modifier=0x3fc817798fd58499 time=2013-09-18 06:02:45 UTC
ComputeNextStakeModifier: prev modifier=0xba202540b22ec501 time=2013-09-18 12:03:42 UTC
ComputeNextStakeModifier: prev modifier=0xa8b1bafe6ce3d92c time=2013-09-18 18:00:51 UTC
I'm not a pro so I might be reading this wrong. It looks like it's trying to submit a PoS block and the network isn't taking it? Then when a new block comes along from the network it just drops the PoS block..
ComputeNextStakeModifier: prev modifier=0x3fc817798fd58499 time=2013-09-18 06:02:45 UTC
ComputeNextStakeModifier: new modifier=0xba202540b22ec501 time=2013-09-18 12:01:44 UTC
SetBestChain: new best=00000007ecaeca0c5c27 height=217576 trust=7562537080695 date=09/18/13 12:03:42
ProcessBlock: ACCEPTED
received: inv (37 bytes)
got inventory: block 00000007ecaeca0c5c27 have
sending: getblocks (965 bytes)
force request: block 00000007ecaeca0c5c27
sending: inv (37 bytes)
received: inv (37 bytes)
got inventory: block 00000007ecaeca0c5c27 have
sending: getblocks (965 bytes)
force request: block 00000007ecaeca0c5c27
received: inv (37 bytes)
got inventory: block 00000007ecaeca0c5c27 have
sending: getblocks (965 bytes)
force request: block 00000007ecaeca0c5c27
received: inv (37 bytes)
got inventory: block 00000007ecaeca0c5c27 have
sending: getblocks (965 bytes)
force request: block 00000007ecaeca0c5c27
sending: inv (37 bytes)
received: inv (37 bytes)
got inventory: block 00000007ecaeca0c5c27 have
sending: getblocks (965 bytes)
force request: block 00000007ecaeca0c5c27
received: getblocks (965 bytes)
getblocks -1 to 00000000000000000000 limit 500
Flushing wallet.dat
Flushed wallet.dat 73ms
received: getblocks (965 bytes)
getblocks -1 to 00000000000000000000 limit 500
Flushed 12388 addresses to peers.dat 33ms
received: inv (37 bytes)
got inventory: block 00000007801f1bfe7dbf new
askfor block 00000007801f1bfe7dbf 0 (00:00:00)
sending getdata: block 00000007801f1bfe7dbf
sending: getdata (37 bytes)
received: block (6188 bytes)
received block 00000007801f1bfe7dbf
ComputeNextStakeModifier: prev modifier=0xba202540b22ec501 time=2013-09-18 12:03:42 UTC