A image usually has multiple references, so as long as one of the references has io.cri-containerd.pinned=pinned label, then the image is pinned.

Reproducing current issues

$ ctr -n k8s.io images pull --label=io.cri-containerd.pinned=pinned docker.io/library/busybox:1.36
$ crictl --debug images
// ignore something
&Image{Id:sha256:a416a98b71e224a31ee99cff8e16063554498227d2b696152a9c3e0aa65e5824,RepoTags:[docker.io/library/busybox:1.36],RepoDigests:[],Size_:2224229,Uid:nil,Username:,Spec:nil,Pinned:false,}

Of course, if we ctr manually remove the image reference containing the label, Pinned will still be true, but will become false after restarting.

Although it would be possible to set Pinned strictly based on the labels of the image references, it would be complicated to keep track of each image reference, and I'm not sure it's necessary to do so.