Well, anyone looking at the CDF, that 0.98 means that all pools should average one block like that or longer in every ~50 blocks.
That being the pool's 25th successful block, means it's not at all unexpected.
But at least the average since the pool started is still looking pretty good
69.52% of diff average per block.
i.e. we've found ~1.44 times the number of expected blocks so far.
A long block like that indeed affected those two numbers as I said in that post on the previous page, but that luck streak before has kept the average better than expected.
Of course if you start mining at any time, the expected long term average is 100%, but the shorter term average will of course vary a lot more.
That all being said, the one thing that makes that guaranteed variance easier to bear with PPLNS, is the higher pool hash rate.
We are slowly climbing up there, but of course the more hash rate the better
1700TH means at the moment an expected average block time of ~1day 4.25hrs so it's getting better