Indeed.
Maybe it's his pal, to whom he sold a pile of Dash, carrying out a precision liquidation of 1013 Dash every 90 minutes
Did you say 1,013 every 90 minutes? How many of these? BTW - all these nonsense trades of 0.05147962 DASH etc., these are robots? Where are they coming from?
could these dumps perhaps be from Bitfinex ? dumping any leftover Dash they still had in possession onto Cryptsy ?
Not possible. As per https://www.bitfinex.com/pages/announcements/?id=49, Bitfinex allows you to withdraw your coins until midnight UTC on September 30, 2015. In addition:
So seems like they won't sell off anything.