Does this mean Prosper is getting lazy with collections or with borrower screening again?
Hard to say. It could be that Prosper is getting desperate to get loans through the door so they are letting stuff slide that they shouldn't.
Or is this poor performance caused by the Prosper update fiasco?
If I were to make a guess, I would say that when prosper first opened up for business again, there were a lot of lenders who had finally had a chance to see their portfolios crash & burn. I would suspect that very few lenders were putting any money into it (loan volume was low) and competition for good loans was low, so fewer questionable loans were made.
As Prosper stayed open for business longer, more dumb money followed in, making foolish choices, relying on Prosper's new grading system and generally causing more competition for good loans. Thus more poor loans were made.