500 'an error occurred fetching the job' when viewing some job logs when not logged in

Summary

When viewing a job log when not logged in, it fails. It only happens with some job lobs.

Steps to reproduce

1. Ensure you are NOT logged in (or open a new private window)
2. Open https://gitlab.com/openid/conformance-suite/-/jobs/259713113

Example Project

https://gitlab.com/openid/conformance-suite/-/jobs/259713113

What is the current bug behavior?

'an error occurred fetching the job' appears in a red box

The console shows the issue was a 500 error loading https://gitlab.com/openid/conformance-suite/-/jobs/259713113.json

What is the expected correct behavior?

The log file should appear, as it does if you are logged in, and as other job logs on the same project do.

Relevant logs and/or screenshots

Same thing is reproducible with curl:

curl -v https://gitlab.com/openid/conformance-suite/-/jobs/259713113.json

*   Trying 35.231.145.151...
* TCP_NODELAY set
* Connected to gitlab.com (35.231.145.151) port 443 (#0)
<..>
> GET /openid/conformance-suite/-/jobs/259713113.json HTTP/1.1
> Host: gitlab.com
> User-Agent: curl/7.63.0
> Accept: */*
>
< HTTP/1.1 500 Internal Server Error
< Server: nginx
< Date: Fri, 26 Jul 2019 08:03:43 GMT
<..>

Output of checks

This bug happens on GitLab.com