Feeds without links don’t seem work correctly. As is clear here: validator.w3.org/feed/docs/atom.html the link element is not a required element in the standard (although very common) so I would be most grateful if you could try to fix this issue.
Thanks for your reply. It’s private feeds that I work with so would rather not post it online but it should be quite easy for you to verify the bug by creating a feed without links.
I came across this feed without links that you can use to diagnose the problem: colintoh.com/blog/feed
It seems to be by error that the feed doesn’t have links though so I suspect it might get fixed at some point, but nonetheless it shows that devonthink can’t handle feeds without link elements even though it’s not a required element in the standard.