A custom plugin enabled in a project in 4.13 is disabled when a copy of the project is opened in 4.14

If a project created in 4.13 that contains one or more custom plugins is upgraded to 4.14, the custom plugins are disabled.

1. Create a new code project in 4.13.
2. Add a custom plugin to the project.
3. Open the Plugins window and make sure the new plugin is enabled in the project.
4. Open a copy of the project in 4.14.
5. Open the Plugins window.

RESULT:
The plugin is no longer enabled in the project.

EXPECTED:
The plugin is still enabled as it was in the previous Engine version.