Suddenly when I try to upload an image, I get an error

I get the error Undefined property: stdClass::$image when uploading an image to a page template. The image specific blueprint is here:

            type: file
            label: Screenshot
            limit: 1
            destination: 'self@'
            multiple: false
            style: vertical
              - image/*

The image gets uploaded regardless of error, but the header is not updated…

When I try this on a version from midnight, it works just fine. Is there a limit somewhere on caching? It seems like the system is somehow clogged…

EDIT: It seems to be tied together with the 1.8.2 release of the Admin Plugin as 1.8.1 works fine.
Bug report: