Sam, thanks for filing https://gitlab.com/gitlab-org/gitlab-ee/issues/1575 I've pinged our frontend team.

No worries, hope my report was good enough! Excellent support as always :)

Thanks for helping to troubleshoot in the issue. Our frontend lead and VP of Engineering are on it.

And they swarmed the issue and found the issue (within the nginx config) very odd-ball one indeed that didn't affect everyone, fantastic troubleshooting by all the Gitlab engineers, excellent communication and top-notch support like I've never experienced from any software vendor before. A+++ would commit again ;)