TYPO3 Core

While having to deal with imported HTML from an external service, I encountered this odd Bug where, when a Text is followed by a line break and then followed by a self-closing p-tag, the previous text somehow gets duplicated in the output.

An example looks like this (in my case the html comes from a variable, but works the same):

<f:format.html>This is a weird TYPO3 Duplication Bug
<p/></f:format.html>

The "This is a weird TYPO3 Duplication Bug" text get's duplicated in the output.

I encountered it in TYPO3 9, but could confirm this behaviour in 10 and up to 11.5.4 as well.

I understand that a self-closing p-tag is not really proper html5, but I'd presume any other behaviour would be preferred over this duplication thing.

Greetings