Web IDE duplicated accent character problem

Summary

Error when added a character with accent, Web IDE duplicate the character.

Steps to reproduce

Insert any accent in the text, Web IDE will duplicate the character.

Example Project

What is the current bug behavior?

Duplicate the character when accent included

What is the expected correct behavior?

Only include one character.Grabación_de_pantalla_2019-10-01_a_las_16.35.00

Relevant logs and/or screenshots

attached video example

Output of checks

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

not needed

Possible fixes

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