There have been two insane difficulty spikes.
However most of the POT hashrate doesn't come from one of the listed pools (or I missed it, anyone got a clue?)
http://chainz.cryptoid.info/pot/#!extractionSo any hiccup with the majority holder will result in massive spikes...
(if you know who that "Unknown" might be let me know, I'll add it, but from the transaction history, it doesn't seem to be a regular MPOS pool)
knc mining in airport hanger alone, or with wafflepool as wafflepool was on our coin before and knc holds 1/2 of hashes they have on their multipool total or possibly more. I know they had at least 1/2 hashes waffle had alone and they added more miners since then as shown in some links I provided previously.