html is corrupted

WP 5.7.1
PHP 7.4.16
SSL Certificate: Valid for both WWW and non-WWW. (This website is non-WWW).

Using a blank slate theme.
Plugins Activated:
ACF Pro
Advanced Custom Fields: ACF Code Field
Phone Number Field for Advanced Custom Fields
Disable Gutenberg
Enable Media Replace
WP Fastest Cache
Password Protected (tried this both active and deactivated, no difference).

I have your plugin working on multiple websites using this theme and these plugins, no issue.

All plugins above are using the latest version, including WPFC.

I checked the W3C validation with direct input and outside of one “error” the site is valid. (The error wouldn’t affect this).

Checked the source code for the plugin, and in /inc/cache.php on line 711 it runs checkHtml($buffer). I checked the “checkHtml” function and found it on line 946. I tried commenting out each of the two checks in that function to see if it would “force” the minification/compression etc. Neither worked.

I am looking at my htaccess, and the WPFC stuff is added in there no problem. There isn’t anything else in my htaccess other than the standard stuff included in “Begin WordPress”.

Any thoughts on how to fix, or what I can do?