Agreement field not validated

[silenzium]

If I enable the aggreement checkbox, a user still can submit the registration form and a user account will be created, since the parent::compile() is executed before the aggreement widget will validate and also in the ModuleRegistration::compile() method the agreement will not be in the list of validated fields, so it doesn't comlain and creates the user.
I also don't get any error messages in the form for the agreement field.

Using Contao 3.5.2

Is this a known bug or am I the only one with this behaviour? I get this in two different projects.

[V15]

I have the same issue. Your fix works fine! Thanks a lot.

[silenzium]

will this be review and merged some time?