shahpharshal priya2810I had reached out to the admission committee for the exact same question about 2 days ago. Here is the response from them -
"Once you receive the link to the video essay, you will have 7 days to complete it. Your application will still be considered as part of round 2 as long as you have submitted all other supplemental items by the deadline."
So it looks like you can complete the video essay after the deadline too, as long as all other aspects of the application have been fully completed.
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