Error in submitting the signup form after unselecting the checkbox

I have an optional checkbox in my signup form.

Initially, I pre-selected this checkbox by passing true to the extension attribute during the OnAttributeCollectionStart event. With this setup, the checkbox appears selected by default.

However, when the user unchecks the checkbox and submits the form, a JavaScript error appears in the browser console.

I also tried removing the attribute assignment from the OnAttributeCollectionStart event. In this case:

The checkbox is not selected by default

Submitting the form without interacting with the checkbox works fine