Can no longer edit file from merge request as project owner

When I am in a merge request, in the changes tab, I can use the Edit button.

Behavior until updating to 11.3.4: GitLab opens a text editor to add a single commit for a single file.

Behavior with 11.3.4: GitLab CE tells me "You're not allowed to edit files in this project directly. Please fork this project, make your changes there, and submit a merge request."

According to the projects Settings -> Members, I am the owner of the project.