Secret TAG Dynamic Cache visible on uncached first load.

As Dravon5X said on thread from December 2017, "after cache deletion, first visitor will see secret tag. Only 2nd and next visitors will see correct replacement of Secret TAG."

Enable dynamic caching is on.
Late Init is on.
First load thus shows secret tag and is a security issue.

Please check : https://github.com/Automattic/wp-super-cache/issues/490

Start by reading the linked issue #490 and reproducing the first uncached load with Enable dynamic caching and Late Init enabled. Done means the first visitor after cache deletion never sees the secret tag and receives the correct replacement instead.

Written by the indexing model from the issue text.