I use newsblur a lot (paying customer) and it works great on Android but on Desktop it has trouble on this one site (https://www.mbl.is/feeds/innlent/) where it sometimes refuses to fetch snippets. Not on all news items, but it is pretty frequent (45% maybe? Guessing). The RSS Extension for Chrome shows all of these items correctly and the Newsblur Android app does also so I don’t think it is a problem with the RSS, but Newsblur on desktop shows a mostly empty snippet (see photo).
By the way, the screenshot is depicting this item from the site: