Hi @Sen-Sai, thanks for taking the time to report this!

Could you please elaborate on "This alters a tag extensions nowiki typemarker." ?

(Removed Gerrit tag as this is unrelated to Gerrit's codebase itself.)

Sure,
With a tag extension you set a hook that can be used :
e,g,

$parser->setHook( 'wsform', 'WSFormHooks::WSForm' );

When its invoked it will call the (in this case) WSFormHooks::WSForm function.
The function returns its content this way :

return array( $htmlContent, "markerType" => 'nowiki');

It should mean to output whatever I give back. This always worked fine. But with the change made that I mention here the ( Sanitizer::armorFrenchSpaces( $text ); being moved down in the code ) it messes up output and replaces spaces with

 

in certain conditions before a ! or =
and my wiki is not even French :-)

As I mentioned in the task description reverting this https://gerrit.wikimedia.org/r/c/mediawiki/core/+/593017 solves the issue