OK. Thanks for posting the video. Helped a lot to see the problem. There are two possibilities I can think of:
1. The 12MHz crystal (for microcontroller) is not soldered well or defective, causing the system clock to slow down significantly.
2. There is an issue with RTC (either loose connection or defective chip) that causes the microcontroller to have difficulty reading the RTC.
This is a rather unusual problem, you can send an email to [email protected]y.net to arrange for support.