yes you are right, I just switch to another theme and problem is gone.

It is not on the extension,
it is the regular order settings, I have the following settings;

1, free delivery when order> 50
Fixed delivery fee $6

2, discount on self-pickup 10% off

3, standard discounts
Order > $25 get $4 off

If the order is for delivery, discount works fine.
if the order is for self-pickup, it will apply both 10% and $4 off if the order is over 25.

Hello Olly
Thank you so much for your answer, It is really helpful !!

Andrew