Thank you jonnyb.
Learn something everyday, but this is still going on.
why do some p2pools have stratum in address, are they not true p2pools?
(this particular pool does not)
p2pool supports the stratum protocol, so when you connect, you can either use stratum+tcp:// or http://. As for why you're still getting coin, it's completely dependent upon how long shares remain valid on the chain. For example, in Bitcoin, each block pays out the previous 8640 shares - which is 3 days worth of shares.