TYPO3 Core

I noticed this problem, when my log had some entries, which looked like this:

Wed, 22 Nov 2023 12:49:32 +0100 [ERROR] request="6c4905c77d33f" component="TYPO3.CMS.Core.TypoScript.IncludeTree.Visitor.IncludeTreeConditionMatcherVisitor": Expression could not be parsed. - {"expression":"traverse(page, \"uid\") {$searchformPid}"}

This is only relevant for the Frontend and it works in this context. But when I open an Extbase backend module e.g. The Backend User Administration module, this error gets logged.
In the Bootstrap process of Extbase, the first site is fetched (as there is no site context in BE) and then the TypoScript is loaded from there.

How to reproduce:

1. Add site settings for the first site: customPid: 1
2. Add some TypoScript for the Frontend e.g.:

page = PAGE
page.9999 = TEXT
page.9999.value = Pinguin
[traverse(page, "uid") == {$customPid}]
    page.9999.value = Känguru
[end]

3. Visit the frontend and have a look at the log file. It should be empty.
4. Now go to the backend and open the Backend User Management Module.
5. You should see the log entry:

Wed, 22 Nov 2023 14:19:58 +0000 [ERROR] request="b9f181abd3a67" component="TYPO3.CMS.Core.TypoScript.IncludeTree.Visitor.IncludeTreeConditionMatcherVisitor": Expression could not be parsed. - {"expression":"traverse(page, \"uid\") {$customPid}"}