Billing address form missing in checkout since upgrade to Magento 2.4.4

since upgrading my Magento instance from 2.4.3 to 2.4.4, the onepage checkout is missing the form for the billing address.

After unchecking the checkbox for “same as shipping address”, the address simply disappears without showing the form as before.

I removed all corresponding layout files (Magento_Checkout) for the used theme, but the problem still persists.

Did anybody come across this error and find a fix for this?

UPDATE
After fiddling around mit some Third Party Modules and my own stuff – thanks to Tu Van – it turned out, that one of my own modules was defect and causing the billing address form from showing.

So if you ever come across this, check first, if you implemented a defect address validator (like in my case) or installed a broken module.

Thanks in advance,
Manuel