This problem can occur with the bag that has gusset and bottom seal.
In our production, we have checked leaking by adding air into the bag which it maybe not enough and hard to detect.
So we need to get how the customer test leak for our bag which we can see the red color liquid to detect the problem.
We would like to know when red liquid is added, customer have applied the force to check leak or not.
For this problem, we would like to know it has high effect with customer product or not.
Could you ask customer to special accept it ?
If customer are able to special accept we will improve the leaking test method as same as customer test.
So next order, the bag will have been checked leaking follow customer method.
If it has high effect with customer product.
Can we try to rework the seal area at the leak position?
For this way the bag will not be beautiful at the seal position.
Even though the product have been reworked, we are not sure all bag will not leak because we use manual seal which hard to control the pressure of sealing.
Please update information to me