Conditional Logic with multiple forms on the same page not working

Problem

I have a page with two Webforms, Form A for contacting the admin and Form B for ordering something. In both of them I have some conditional logic. In the second form (Form B) I want to add conditional logic to the phone-field to hide it until the firstname-field is filled (just a simplified example). The firstname-field exists in Form A and B.
The problem is now, that the logic for Form B works with the fields of Form A. When I add a firstname in Form B, phone-field of Form B stays hidden. When I add a firstname in Form A, phone-field of Form B will be visible.

Proposed resolution

I do not know exactly the code of the webform-module. But I think the conditional logic on a single page does not distinguish between multiple webforms on the same page.

The simplified code of the two forms.

Form A

firstname:
  '#type': textfield
  '#title': Firstname
  '#required': true
lastname:
  '#type': textfield
  '#title': Lastname
  '#required': true
contactmeby:
  '#type': radios
  '#title': 'Contact me by'
  '#options':
    Phone: Phone
    E-Mail: E-Mail
  '#required': true
phone:
  '#type': tel
  '#title': Phone
  '#states':
    visible:
      ':input[name="contactmeby"]':
        value: Phone
    required:
      ':input[name="contactmeby"]':
        value: Phone
  '#international': true
  '#international_initial_country': CH
e_mail:
  '#type': email
  '#title': E-Mail
  '#states':
    visible:
      ':input[name="contactmeby"]':
        value: E-Mail
    required:
      ':input[name="contactmeby"]':
        value: E-Mail

Form B

firstname:
  '#type': textfield
  '#title': Firstname
  '#required': true
lastname:
  '#type': textfield
  '#title': Lastname
  '#required': true
phone:
  '#type': tel
  '#title': Phone
  '#states':
    visible:
      ':input[name="firstname"]':
        filled: true
  '#international': true
  '#international_initial_country': CH
orders:
  '#type': own_order_element
  '#title': Orders