Disabled previous button enables itself after validation on site

Hi there!

Scenario: I have the previous button enabled via settings. I want to disable it after a specific page. That works fine with JS
Qualtrics.SurveyEngine.addOnReady(function () {
this.disablePreviousButton();
});

The problem: If I do not answer an enforced question the validation reminds me kindly of this. So far so good. But! The previous button gets enabled in the same step.

Can someone replicate this behavior? I tried also (addOnload and addOnUnload). Same behavior for me.

Appreciate any input on this!