Comment 2 for bug 1959186

this is a known limitation of ceph backed glance images.
a snapshot is just a special case of this.
it not a nova bug as this is expected to happen when we do a shallow clone.

there have been some feature request in the past tho allow breaking this chain but to me this is not a bug. we will discuss this in the nova meeting in the open discussion section shortly.

so i will not update this yet.