Merge Request Diffs Error

This error is occurring when you try to view the differences in the merge request.

I tried to simulate the same problem on gitlab.com but, it's working.

Gitlab CE 11.4.5 (Ubuntu 16.04, Omnibus)

production.log

Encoding::UndefinedConversionError ("\xFF" from ASCII-8BIT to UTF-8):
  app/controllers/application_controller.rb:114:in `render'
  app/controllers/projects/merge_requests/diffs_controller.rb:34:in `render_diffs'
  app/controllers/projects/merge_requests/diffs_controller.rb:14:in `show'
  lib/gitlab/i18n.rb:53:in `with_locale'
  lib/gitlab/i18n.rb:59:in `with_user_locale'
  app/controllers/application_controller.rb:424:in `set_locale'
  lib/gitlab/middleware/multipart.rb:101:in `call'
  lib/gitlab/request_profiler/middleware.rb:14:in `call'
  lib/gitlab/middleware/go.rb:17:in `call'
  lib/gitlab/etag_caching/middleware.rb:11:in `call'
  lib/gitlab/middleware/rails_queue_duration.rb:22:in `call'
  lib/gitlab/metrics/rack_middleware.rb:15:in `block in call'
  lib/gitlab/metrics/transaction.rb:53:in `run'
  lib/gitlab/metrics/rack_middleware.rb:15:in `call'
  lib/gitlab/middleware/read_only/controller.rb:38:in `call'
  lib/gitlab/middleware/read_only.rb:16:in `call'
  lib/gitlab/middleware/basic_health_check.rb:25:in `call'
  lib/gitlab/request_context.rb:18:in `call'
  lib/gitlab/metrics/requests_rack_middleware.rb:27:in `call'
  lib/gitlab/middleware/release_env.rb:10:in `call'

production_json.log

{
    "method":"GET",
    "path":"/automacao/automacao-cisspoder/merge_requests/1862/diffs.json",
    "format":"json",
    "controller":"Projects::MergeRequests::DiffsController",
    "action":"show",
    "status":500,
    "error":"Encoding::UndefinedConversionError: \"\\xFF\" from ASCII-8BIT to UTF-8",
    "duration":568.75,
    "view":0.0,
    "db":20.48,
    "time":"2018-11-09T10:16:59.365Z",
    "params":[ {
        "key": "namespace_id", "value": "automacao"
    }
    ,
    {
        "key": "project_id", "value": "automacao-cisspoder"
    }
    ,
    {
        "key": "id", "value": "1862"
    }
    ],
    "remote_ip":"172.16.104.22",
    "user_id":75,
    "username":"michelheydt",
    "ua":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36",
    "gitaly_calls":4
}

Images

• In my fork when requesting the merge request it is possible to visualize the differences

• After opening the merge the differences are not possible to visualize