This is not a valid glance bug. Once the image data is set, no one is allowed to change the disk_format, container_format, size, or checksum. This is by design. It is particularly the case for snapshots, where Nova knows exactly what it is dealing with and will set the disk_format and container_format correctly.
Additionally, it is possible to change the disk_format and container_format on images in 'queued' status using the Image API.
This is not a valid glance bug. Once the image data is set, no one is allowed to change the disk_format, container_format, size, or checksum. This is by design. It is particularly the case for snapshots, where Nova knows exactly what it is dealing with and will set the disk_format and container_format correctly.
Additionally, it is possible to change the disk_format and container_format on images in 'queued' status using the Image API.