CREATOR OWNER access control entries should always be inherit-only, because it doesn't make sense for them to apply to any actual object. When using recent versions of Windows with the modern API, all CREATOR OWNER entries are automatically marked inherit-only.
In the advanced GUI, the inherit-only flag translates as "Subfolders and files only". Changing it to "This folder, subfolders and files" would have the effect of clearing the inherit-only flag, which can't be done for CREATOR OWNER. The basic GUI should probably not be showing this as Special, but I guess MS didn't think of this special case.