BUT YOU SAID PECOTA IS NEVER WRONG!
I have yet to go an off-season without hearing something like this, despite also having yet to ever see anyone say PECOTA is never wrong, as a projection system will always be to a degree as long as it's merely a system of educated guesses. (PECOTA just happens to be more educated and reliable than anyone else you know.)
In any case, Sky Andrecheck at The Baseball Analysts takes an early look at what mistakes PECOTA may have made based on the first three weeks of the season, with a discussion of actual mistakes versus mistakes made with simple poor luck (teams exceeding their "true winning percentage" over a sample of 162 games which is still rather small).
It includes a look at the very surprising Marlins, with an analysis of how good they've been, how good PECOTA expected them to be, and then a combination to make a more educated guess at how good they really are. There's a lot of great statty meat in there, as well, for the purposes of you super baseball geniuses out there.
Most awesomely to me, though, is a full projection of standings using the combination of actual three-week data and pre-season projections. Congratulations to the Cleveland Indians on winning the division with a .500 record!