Finished Product Packaging Bloating

Hello all our Company is a Flexible Packaging. We produce stand-up pouches for Sauces like Carboara and Spaghetti Sauce.

One of our client is frequently encounter bloating products, twice a year but a very minimal in Quantity of bloating.

Item is for Carbonara retortable products. Bloating were seen after 14 days of incubation. As far as I know if the pouch have a weak seal after retorting process, pouch may burst since strong pressure is present during retort process. Issue on weak seal on side on bloated packaging material is not an issue anymore I think. And if bloated packaging have no leaking during bubble test, what is the possible reason why the pouches may bloat? Product were cooked inside the retortable with121 deg. C for about 35 mins and the cooling process is around 26mins. Hoping you can share your idea and experience on this. Thank you,

Of hand, this really sounds like a processing issue to me. If the packages are not leaking than it has to be the process

Is the customer overloading the machine causing the centre packages to not meet the required time/temp in the geometric centre of all pouches?

Do they have a scheduled validated process for the retort of each recipe?