@valantis_c,
One other idea. It could also be that the feed is not the problem, but the browser you are using. If you open the feed in a different viewer, like a text editor, the feed loads without issues. You can also try to open the feed in the source viewer (open the page in your browser, right-click on the page and select the “view page source” option). The feed will show up correctly again.
You could offer the feed to Google, and I expect it will just be accepted as it is.
Let me know your thoughts on this topic.