Order of text filters not respected when changed in some subcontexts

Description of the problem:

1. Assuming you have filter urltolink and mediaplugin active on your site and in this order.
2. Create a course, add a label and - without making a link - past a url of a video in the label.
3. Confirm that the video is embedded.
4. Now edit the course to change the status of the filter mediaplugin from "Default ( on )" to "on" and save the changes.
5. Go back to the course view page.
6. Confirm that you find only a link to the url without any embedding.

(See attached video for a demonstration)