Disabled system add-on enabled automatically

Summary

Documentation theme add-on can get enabled automatically when we re-enable Confluence Quicknav add-on

Environment

Confluence 5.9.2 , 5.9.4

Steps to Reproduce

1. Go to Manage add-ons and view all add-ons
2. Disable Confluence quicknav add-on
3. Disable Documentation Theme add-on
4. Enable Confluence quicknav add-on
5. Refresh the page and look for Documentation theme add-on

Expected Results

The Documentation theme add-on should remain disabled

Actual Results

The documentation theme add-on is enabled automatically

Additional Notes

Affects the below system add-ons as well

1. Confluence Easy-User Admin