If a page has a canonical tag to an URL that is currently blocked by robots.txt, ahrefs sees the page as not indexable, but doesn't flag it as an issue as there is no issue configuration option for this kind of scenario.

Since a canonical tag to a disallowed URL can be a significant SEO problem, in addition to being able to configure issues for "Canonical points to 4xx", "Canonical to points to redirect", etc., it would be nice to also have a "Canonical points to disallowed URL" option.