Bug Description:
Following the latest stream titled "Testing in Production," a bug has emerged wherein any new progress made in the cohort is not being saved. The "Mark as Complete" button also fails to function properly. Despite temporarily displaying as "Mark as Incomplete" upon completion of video content, it reverts to "Mark as Complete" and restarts from the old timestamp upon reloading.

Steps to Reproduce:

1. Navigate to any video within the cohort.
2. Attempt to complete the video.
3. Notice that completion is temporary and reverts upon reloading.

Expected Behavior:
Upon completion of the content, a green tick mark should appear next to the video. Similarly, clicking the "Mark as Complete" button should exhibit consistent behavior.

Additional Information:

• Browser: Brave