gitlab_project_mirror: Attribute "mirror_branch_regex" always shown as changed in diff

Since provider version 17.10 the gitlab_project_mirror shows as "updated-in-place" because of the attribute mirror_branch_regex which will be added (known after apply). So on every plan, all gitlab_project_mirror now always appears as changed. Even after applying this, during the next run it will be shown as to be changed again.

  # module.projects.gitlab_project_mirror.main["foo"] will be updated in-place
  ~ resource "gitlab_project_mirror" "main" {
        id                      = "0000000:0000000"
      + mirror_branch_regex     = (known after apply)
        # (7 unchanged attributes hidden)
    }

This is the mirror configuration used

resource "gitlab_project_mirror" "main" {
  project  = 0
  url      = "https://user:password@git.example.org/path/to/repo.git"
  enabled  = true

  keep_divergent_refs     = false
  only_protected_branches = true
}

The mirror is currently configured with only_protected_branches. Trying to set this new attribute mirror_branch_regex to an empty string results in an error.

│ Error: Invalid Attribute Combination
│ 
│   with module.projects.gitlab_project_mirror.main,
│   on ../../modules/gitlab-projects/push_mirror.tf line 18, in resource "gitlab_project_mirror" "main":
│   18:   only_protected_branches = true
│ 
│ Attribute "mirror_branch_regex" cannot be specified when
│ "only_protected_branches" is specified
╵
╷
│ Error: Invalid Attribute Combination
│ 
│   with module.projects.gitlab_project_mirror.main,
│   on ../../modules/gitlab-projects/push_mirror.tf line 19, in resource "gitlab_project_mirror" "main":
│   19:   mirror_branch_regex     = ""
│ 
│ Attribute "only_protected_branches" cannot be specified when
│ "mirror_branch_regex" is specified

How should the mirror_branch_regex attribute be set on a mirror to not always show as changed?