Reddit had a bug in their RSS generation which was fixed just a second ago.
https://old.reddit.com/r/bugs/comments/mi17dt/reddit_rss_feeds_broken_pubdate_used_in_atom_feeds/

Can you send the URLs of the other two feeds (non-Reddit) at are causing problems to feedbro.reader@gmail.com please?

PS. Facebook group parsing is also broken in 4.9.5 (due to Facebook API change) but 4.9.7 is in the manual AMO review queue which should fix that.