Logout bug when Guest caching is enabled

[K a M a L]

The issue described here https://xenforo.com/community/threads/guest-page-caching.164816/ has been existing for a long time with no resolution .. I tried doing some troubleshooting to see the reason behind it because it was really annoying , I found the bug is very simple
at method PageCache->getCachedPage() .. there is a call $response->replaceHeaders($result['headers']);
result header will typically look like
Code:

array (size=5)
  'X-Frame-Options' => string 'SAMEORIGIN'...

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