Multi-page form breaks when required element hidden by previous page

When a required element in a multi-page form is hidden due to the value of an element from a previous page, the user cannot navigate out of the page which contains the hidden/required field. This was working properly in 5.0-beta24 AFAIK.

Use the following YAML code to reproduce:

step_1:
  '#type': wizard_page
  '#title': 'Step 1'
  my_checkbox:
    '#type': checkbox
    '#title': 'My Checkbox'
    '#description': 'Check this to reveal a required field in Step 2. If you don't check this you will be stuck at Step 2.'
step_2:
  '#type': wizard_page
  '#title': 'Step 2'
  my_number:
    '#type': number
    '#title': 'My Number'
    '#required': true
    '#states':
      visible:
        ':input[name="my_checkbox"]':
          checked: true
    '#default_value': '1'
    '#min': '1'
step_3:
  '#type': wizard_page
  '#title': 'Step 3'
actions:
  '#type': webform_actions
  '#title': 'Submit button(s)'