img要素にdecoding属性をつけるとvaldiator.nuでエラーが出るのはなぜですか

Question

img要素にdecoding属性をつけるとvalidator.nuで以下のエラーが出ます。decoding属性を消すとこのエラーはなくなります。

Error: Attribute decoding not allowed on element img at this point.

From line 22, column 70; to line 22, column 165

 href="#"><img class="image logo__image" src="/assets/images/logo.png" alt="The Company" decoding="async"></a></

Attributes for element img:
Global attributes
alt — Replacement text for use when images are not available
src — Address of the resource
srcset — Images to use in different situations (e.g. high-resolution displays, small monitors, etc)
sizes — Image sizes for different page layouts
crossorigin — How the element handles crossorigin requests
usemap — Name of image map to use
ismap — Whether the image is a server-side image map
width — Horizontal dimension
height — Vertical dimension
referrerpolicy — Referrer policy for fetches initiated by the element
decoding — Decoding hint to use when processing this image for presentation

Attributes for element img: の部分でdecoding属性も挙げられているのにエラーが出るので不思議です。これはなぜで、またどうしたら改善できるのでしょうか？