Previous issue description persists when creating a new issue in specific scenario

Summary

The previously saved issue's description persists when immediately creating a new issue. This is only happening in Firefox (78.0.1 x64). It works as expected in Chrome (83.0.4103.116 x64). I am using MacOS and cannot test this in Windows or Linux.

Steps to reproduce

  1. Start creating a new issue.
  2. Fill in the title and description.
  3. From the description editor, hold command (ctrl on Windows?) and press enter to submit the issue.
  4. From the issue screen, press i or click New Issue to create a new issue.
  5. The description from the first issue remains in the description box.

Example Project

(If possible, please create an example project here on GitLab.com that exhibits the problematic behavior, and link to it here in the bug report)

(If you are using an older version of GitLab, this will also determine whether the bug is fixed in a more recent version)

What is the current bug behavior?

Previously saved issue description persists into new issue.

What is the expected correct behavior?

The new issue should use the default issue template or be blank.

Relevant logs and/or screenshots

https://youtu.be/HZyXYl1zO1Q

Output of checks

(If you are reporting a bug on GitLab.com, write: This bug happens on GitLab.com)

This bug happens on GitLab.com

Results of GitLab environment info

Expand for output related to GitLab environment info 
(For installations with omnibus-gitlab package run and paste the output of:
`sudo gitlab-rake gitlab:env:info`)

(For installations from source run and paste the output of:
`sudo -u git -H bundle exec rake gitlab:env:info RAILS_ENV=production`)

Results of GitLab application Check

Expand for output related to the GitLab application check 
(For installations with omnibus-gitlab package run and paste the output of:
sudo gitlab-rake gitlab:check SANITIZE=true)


(For installations from source run and paste the output of:
sudo -u git -H bundle exec rake gitlab:check RAILS_ENV=production SANITIZE=true)


(we will only investigate if the tests are passing)

Possible fixes

(If you can, link to the line of code that might be responsible for the problem)

Edited by Brett Kinnamon