Slack commands for creating issue displays error but creates issue

Earlier today, I was using slack commands to slackbot to create gitlab issues. I was sending the following:

/gitlab-ce issue new Remaining fixes for mattermost and slack command integration page
The following fixes need to be made:
- Adding autocomplete off to the token input field
- Updating the help document images to match the latest screenshots

As mentioned in https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/8491#note_22946084

/assign @lbennett 
/label ~Frontend 
/label ~Deliverable 
/milestone %8.17

Slackbot kept saying that the command failed and to contact @ayufan but I was surprised to see the following in the issues page after trying multiple times: