Dear Hiring Manager,
I've gone through the video you'd attached and, the problem of the dates you are facing could be due to the API not responding and or unable to fetch the data from the next another file.
There is a possibility of any other reason of this bug, and I would be able to tell you once I review the complete code and test each module of the application.
Please let me know you good time for a detailed discussion over a quick call, so that I can provide you a much better quote.
Looking forward to working with you.
Thank You.