It's possible. I've looked at some feed sources and didn't see anything obviously wrong. I suspect TheOldReader also because if I go to view only a specific fee

It's possible. I've looked at some feed sources and didn't see anything obviously wrong. I suspect TheOldReader also because if I go to view only a specific feed, the entries are sorted correctly newest-first, but displayed publish times go something like "... February 2003; ... January 2003; ... September 2020; 2 hours ago" but on hover the "September 2020" and "2 hours ago" change to their correct 2003 publish dates.