A recent update to WP 3.9.1 has caused an RSS Feed I'm working on to stop working (It was fine pre-update). The error is when you visit the ?feed=rss2 page, and spits out the following:
This page contains the following errors:
error on line 2 at column 6: XML declaration allowed only at the start of the document
Below is a rendering of the page up to the first error.
(and it's a blank page)
Anyone seen this before and know the best fix?