Is it spooky that they said they looked inside a customer's image to fix this? A bunch of engineers just had access to their customer's intellectual property, security keys, git repos, ...
I did a little research on this company. It’s related to (or wholly owned by) a Chinese entity called Labring. LinkedIn shows practically nobody related to the company other than its marketing team. Something smells incredibly fishy.
If you are adding security keys and git repos to your final shipped image you are doing things very wrong - a container image is literally a tarball and some metadata about how to run the executables inside. Even if you need that data to build your application you should use a multi-stage build to include only the final artifacts in the image you ship.
For stuff like security keys you should typically add them as build --args-- secrets, not as content in the image.