This is a user forum and ACF developers do not answer questions here.
Someone can try to help you but you’ll need to provide more information. With the information you’ve provided I can give you some general reasons that this happens.
If the page you are editing has many fields it could be an issue with the php setting “max_input_vars”
Another possible issue is that another field with the same name is interfering with saving the value.
If you want to contact the developers directly you need use the contact form or submit a ticket through your account.
You’re video does not really help me. How many fields are you dealing with? How many rows have you added to repeaters and flexible content fields? How many other fields are on the page?
