For the last week or so, the feed for https://www.macupdate.com/rss has been showing every entry twice. For the last few days, the number of unread articles has been doubled, and reading through the list requires doing a reload of the feed when you’ve gotten to the end of the list, then reading through the exact same articles a second time.
In other words, the feed might show 10 unread articles. Scrolling through it only presents 5 articles to view. Then you reload the feed and see 5 “more” articles that are the same as the 5 you just read.