I was having this issue, and patch in #12 fixed it up without any changes to reverse proxy.
I'm getting the following error when trying any of the links provided by admin_toolbar_tools:
Redirects to external URLs are not allowed by default, use \Drupal\Core\Routing\TrustedRedirectResponse for it.
I will be providing a patch for people to test when they encounter the same problem. I will try to give more information on my environment later.
Closed: cannot reproduce
2.0
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It's likely this issue predates Contrib.social: some issue and comment data are missing.
I was having this issue, and patch in #12 fixed it up without any changes to reverse proxy.