The most possible reason is your wall button press time is longer or shorter than normal operation time (2 seconds press time defaut in our setting).
Steps to set the customized door opening time
1. Go to your Device settings -> Advance settings -> Trigger duration, choose proper time for your actual wall button press time.
If above points do not help, please email below information to firstname.lastname@example.org, we will help solve the issue timely.
1. Your meross account.
2. Your actual garage door wall button press time.
3. You opener brand, model, and user manual if you have.