[whatwg] The banner-role for headers

[Yuvalik Webdesign]

In section 3.2.6 (Assistive technologies) it states in the table that <header> has an implied ARIA role of “banner”.
However, the spec description of <header> does not comply with the description of the banner-role in the ARIA-spec.
ARIA states:

“A region that contains the primary heading or web site title.
Most of the content of a banner is site-oriented, rather than being page-specific. [...], the author *SHOULD mark no more than _one element_ with the banner role*.”

Which makes sense to me, a banner is not a header.
In other words, if <header> implies a banner-role, it may only be used once on a page unless that role is overridden for additional <header>s.
Is this an oversight in the spec or is this to remain like this? If so, how should this contradiction be approached by designers/developers.

Evert