I can confirm this issue for TYPO3 11 while TYPO3 10 works as expected.

When registering a hook in ext_localconf.php (done in https://github.com/in2code-de/lux/blob/develop/ext_localconf.php#L49) like:

$GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['tslib/class.tslib_content.php']['typoLink_PostProc'][]
    = \In2code\Lux\Hooks\LuxLinkListenerLinkhandler::class . '->postProcessTypoLink';

Email rendering with spam rewrite is broken. Even if the target class and function will not manipulate $parameters or is simply empty.

How to reproduce

Example TypoScript:

config.spamProtectEmailAddresses = 10
config.spamProtectEmailAddresses_atSubst = @<span hidden>no spam</span>

Example Fluid rendering:

<f:link.email email="service@mail.org"/>

Simply register the hook in your sitepackage and let the target function empty.

Output:

// Expected
<a href="#" data-mailto-token="wksvdy4sxpyJsx,myno8no" data-mailto-vector="10">info@<span hidden>no spam</span>mail.org</a>

// Actual
<a href="#" data-mailto-token="wksvdy4sxpyJsx,myno8no" data-mailto-vector="10">info@mail.org</a>

Related to LUX issue: https://github.com/in2code-de/lux/issues/31

Patch set 2 for branch 11.5 of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/76110

Patch set 3 for branch 11.5 of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/76110