I hit the issue just now, should be duplicated with https://bugzilla.redhat.com/show_bug.cgi?id=1508290

*** This bug has been marked as a duplicate of bug 1508290 ***

It sounds to me like they managed to create build objects referencing an image, and then later introduced a policy forbidding the images referenced by those objects, so they can't be rewritten now.

The workaround is to either delete the build objects or loosen the image policy to allow the images they reference.

This isn't a build specific problem, anything that references images could hit this.

Clayton, sanity check my theory please.

So after talking to Clayton this is a known bug in the image policy which is fixed in 3.6.1.  (objects which have not actually changed should not be processed through the image admission policy).

The error here can be ignored and the upgrade can proceed.

I'm not sure exactly what we need to doc, it sounds like we need general instructions that in some cases a migration failure is unavoidable and the upgrade can proceed.  I'm passing this off to Mo since my understanding is he owns migration and should know the more general rules that apply.

The known issues docs should point here and state the possible workarounds as:

1. Manually updating the objects to be compliant with image policy and then re-running migration (this is the safest and ideal option, but may too time consuming)
2. Ignoring these errors, and then making sure the post-migration (i.e. once the server is 3.6.1+) is successful (because that should then be able to process the update in place even with non-compliant objects)

The needinfo request[s] on this closed bug have been removed as they have been unresolved for 1000 days