There are extra spaces at the top of whatever is creating the RSS feed.
This is my preferred way of keeping up with things (as I can use Thunberbird to track the feeds).
Probably quite an easy fix. If you want me to fix it [1] I'm happy to do so.
[1] Following the most recent SOP that I'm aware of i.e.: "you found it, you fix it"..
Just had a look at the RSS conf, flicked some switches and tested it a rss application. It now looks good, seems that all latest posts are available in the feed.
I don't currently have any feeds setup; I did a while back but I appeared to have deleted the configuration whilst trying to get it to work. I'd usually have an "all new" feed.
Unfortunately Thunderbird still isn't happy with the extra space at the start.