After I enabled the minify function for HTML i realized it breakes my feed. I disabled the minify function for feeds, emptied all caches, nothing changed. Then I disabled all HTML minification, emptied all caches, problem still occurs. Disabled minify completely in the general menu.
Now, once out of ~5 times the feed loads correctly. However, once the site is refreshed, it will displayed the messed up version again. After a few refreshes, the feed displays properly again. This only happens for not-logged in users.
Anyone knows what could be going on here?