For anyone else reading this thread, the fix is simple and involves removing only a single blank line. Line 6.
In
templates/default/myfeeds.tplFind at the very top:
Replace with:
In
templates/default/rss_xml.tplFind at the very top:
*}
<?xml version="1.0" encoding="utf-8" ?>
Replace with:
*}
<?xml version="1.0" encoding="utf-8" ?>
To any site owners who use the inbuilt RSS features, sorry for the bug I introduced to 7.5.9. I'm glad the fix is simple though. As gizmo mentioned, its been fixed in the upcoming UBB.threads release. I spent a few hours last night researching why this happens, and all I was ever able to find was, "it just does." lol