That might be a limitation of the card. Feedparser is actually broken for me right now due to an upstream issue in Python 3.7 and haven’t taken the time to downgrade to 3.6, so can’t play around with this, unfortunately.
However, what should work for sure is my config-template-card and the regular markdown-card. You’d do something like this:
type: 'custom:config-template-card'
variables:
- states['sensor.hln'].attributes[0]
entities:
- sensor.hln
card:
type: markdown
content: "${vars[0].title}"