@LsHallo

Hi.  It's so hard to determine the reasons for the abrupt shifts in hashrate of different coins.  So many variables.  Dogecoin, for instance, is a fairly popular coin and a lot of people hold it.  There's a lot of dogecoin speculation.  The price was flat for a while and then surged from like 45 sat to 55 sat.  I'm not sure what it is now.  But price changes like that can impact mining.

Also, you mentioned sexcoin.  Sexcoin is featured in several profit-switching multipools.  Those pools effect hashrates because they back certain coins with a lot of hashpower and then it suddenly drops off when their systems decide those coins are not profitable enough anymore.

A whole other thing is short-term rig rentals.  You can rent a mining rig for as little as 3 hours.  That means you get a massive amount of hashpower for those 3 hours.  I've rented rigs and mined smaller coins and for those 3 hours single-handedly doubled the network hashrate of the coin.

So, really, there are so many coins now with so many different characteristics, and so much access to hashpower on various different platforms, it's virtually impossible to know exactly where the shifts are coming from.  

And miners do not act rationally in the sense that they do not always mine what's most profitable.  Just look at how many SHA-256 coins are out there.  There are dozens all with different rates of profitability.  You would think that naturally all the miners with sha-256 hardware would gradually converge on the most profitable coins, yet all these coins continue to be mined at the exclusion of Bitcoin.  

So, it's jtst to complex to really know for sure.