Q:

Docker push re-sends layers to private repository

I have a base image from which I want to create new images for deploying. The images are built locally and deployed to an internally hosted repository on another server using basic auth. When making changes to the base/deployable images, I have observed that some layers are re-sent even though the repository has already seen them before.
Since layers are 'fixed' and the repository has seen them sent previously by my logged in user, why does docker re-send them when pushing and not just send the new layers?

A:

This seems to be a bug in the current Docker version, where it may send some layers more than one time. See: https://github.com/docker/docker/issues/12489

