I downloaded my pdf from the catalyst store and errata IS included, not tacked onto end.
I went through this by hand when I got my PDF, and all the errata is in there, but its in there in a way that preserved the page layout and page numbering of the PDF as compared to the printed version. So relatively minor changes in text, etc. are included in that spot in the PDF. Things like whole tables have put at the end of the book, even when it seems like it specifies it should be in place. I imagine re-laying, re-indexing, and re-paginating the whole thing is a major operation.
I did check each item in the errata (or at least remember doing so) and they could all be found in the PDF of the corebook I have. You just sometimes had to hunt around.