Can you elaborate on what the issue is or what you are concerned about in this transaction?
Did you have issues receiving your coins?
it looks like poloniex is digging for clams and also it sells it on the market. Imo this is a huge conflict of interests... Maybe they are the misterious digger.
Or... The digger is sending his 4.6 clam outputs to poloniex... Poloniex was the first exchange to have clams, They had a large clam giveaway. I thought it had to do with them digging their clams at that time.