"raw" display for files does not work

Currently using 8.8.3 (EE) running on Ubuntu 16 LTS, unluckily "raw" view does not work at all (my colleagues claim, that it did not work in 8.8 at all!).

For example, there a commited PNG file, which looks fine, while cloning the repository, but does not work in web view.

While trying to open this image and attaching a developer console in Chrome it gives me the following information

As always the production.log does not help at all here. :(

EDIT: The previous version of this issue stated that only binary files are infected, after trying some text-files this seems to be untrue. Even ths CE seems to be infected, see https://gitlab.com/gitlab-org/gitlab-ce/issues/18322