Specific pad url fails to embed

[sunjam]

For some reason I'm having trouble embedding a specific etherpad url into Discourse. All other variations I've tried work... I've also written about this on meta.discourse

When I attempt to paste this url into Discourse, the url is still the only thing shown. Any etherpad variation on the pad name succeeds. You can see the pad at https://pad.riseup.net/p/nbmeeting

Thanks for making this great plugin either way!