The issues tab in Mediavine Trellis serves as a general status page for urls that are queued for Critical CSS, blocked from generating Critical CSS, or have been excluded from Critical CSS.
From this tab you can:
See a list of posts or pages that might have Critical CSS errors on the site. You can also visit this tab to confirm that there are no Critical CSS errors for the site.
If Critical CSS errors do exist, you will be presented with the affected URL/slug. From there you can either disable Critical CSS for that specific url, or fix the error.
If a post or page has been queued for Critical CSS generation, it should be listed here as queued for Critical CSS. No further action will be required by you. Once Critical CSS is generated, the post/page will drop off this list.
There is also an option to bypass Critical CSS on a per post or per page basis:
While disabling Critical CSS on a per post or per page basis can be done on the issues tab illustrated above, you can also disable Critical CSS in the post editor.
This setting can be found in any post/page → Trellis Settings (top right in Gutenberg, typically found below the post editor in Classic) → Disable Critical CSS