Access check problems on add_to_template link

update; we have been running this patch #6 in production for over 12 months now without issues.

Thanks for the patch @kriboogh.
We ran into a different issue with this patch. The url path of the 'add to library' link for each section was always referring to the section with delta 0 (i.e. the first section on the page), which caused this link to always trigger a scroll up to, and save of, this first section instead of the relevant section where the link was clicked. The same behaviour happened for the 'Import from library', where the new section would be added as the first section of the page, regardless of between which sections the link was clicked.
I reworked the patch of #6 for version 1.1.1.

An easy way to see this issue is to enable the core navigation module and then visit /admin/config/user-interface/navigation-block

I approached fixing this in a slightly different way in ✨ Allow filtering between "Section" & "Template" within offcanvas & modal screen Needs work -

Could you please re-test with latest release and let us know if this is still an issue?