Would incorrectly implemented landmarks constitute a WCAG failure?

Greetings, colleagues! I would appreciate your viewpoint on landmarks and 1..3.1 Info and relationships.
I understand why landmarks are not required by this success criterion, as other techniques could be used to programmatically communicate the regions of a page.
However, what if a landmark is not implemented as specified in the WAI-ARIA Authoring Practices 1.1<https://w3c.github.io/aria-practices/#aria_landmark>?
Some examples:

  *   A page has two main landmarks.
  *   The main landmark contains banner and contentinfo landmarks.
  *   A page has multiple navigation landmarks, and they do not have unique labels.
  *   A page's primary content is contained in a "Getting started" region (an HTML5 section element that uses the page's <h1> element as its label).
In your opinion, which - if any - of these examples constitute failures of 1.3.1?
Thank you!
Lisa Louise Davis, Accessibility Tools PM