Newsblur on ios frequently crashes on me when marking all articles read. I’m on ios 7.0.3 on an iphone 5.
Same happens on iPad too (iPad Air, 7.0.3)
Same see this more on iPhone 5 than iPad, but when marking a feed, or folder, with a large number of unread items as read the app often pauses and then crashes.
Both devices are updated to most recent version of iOS.