Possibly related:
Suggests a problem with docker vs. AWS perms:
“Today I stumbled upon the same issue. The docker buildx build … --push command failed with the same error message (unexpected status from HEAD request to : 403 Forbidden). But docker push was working uninterrupted. It turns out that buildix required one additional AWS ECR permission - ecr:BatchGetImage.
”
I know nothing about this stuff, but hope that clue might help those who do 