This may be a bug in the external links module.
Using ckeditor if a url is immediately preceded by a right indent it does not appear as a link.
If there is a right indent and any text before the url it works and appears as a link.
Also if the url is not preceded by any text and there is no right indent it works.

Comments

Status:Active» Postponed (maintainer needs more info)

Could you please provide a screenshot? Also is this a problem in 7.x?