I noticed that too. I suppose it could be part of the reason why there's been more unconfirmed transactions and slower transaction times over the past few days.
Maybe an entity like Bitmain initially pumped the number of Segwit transactions on the network (just like they do with spam), to build the perception of a decline in adoption as we head into the Segwit2x fork?
Seems unlikely. If they were doing that then they would directly have been sending spam transactions.
Not sending spam transactions anymore would surely decrease the amount of congestion, so it would have to be a pretty complicated and well orchestrated attack which I don't see any evidence of.
I can't personally find any major services that have stopped taking SegWit transactions, and the ones I'm using still are, so it's certainly odd. I can't think of any explanation though.