Can different permalink settings on sites cause RSS error?

On the site http://newsthatmoves.org we have several subsites for the different languages.

But since a few days ago, since the server wasn’t working and the site was down for a while, the RSS feeds for 3 of them haven’t been working, for example
http://newsthatmoves.org/en/?feed=rss2 just redirects to the homepage and is not valid.

However, curiously, on the greek site, the permalink structure is different (has always been) and the RSS feed works there: http://newsthatmoves.org/el/feed/

I originally thought this was caused by the https redirects, but it seems thats not the case.

I’m wondering if this issue can be caused by some multisite permalink settings?
(I don’t want to change permalink structure unless it is absolutely necessary.)