Running Magento 2.1.10 CE, with multiple stores.
Client requires login to access the site
Running into an issue where one of the client is having a problem with cart. They have added 53 products in their cart, but when they try to update the cart, by adding a new item or editing quantity of an existing, The allowed memory gets exhausted. No matter how much i increase the memory size (now 3GB), it still get exhausted, pointing to a memory leak. This also happens on checkout page. (before showing the payment methods)
I created a test user account on the site and replicated the above user cart. For this user, i have no issues, i can add more items, update quantities for already added ones, and even complete the checkout.
I have checked the values for the both customers, and they are pretty much similar apart from unique values such as email etc
I am currently running out of idea how to debug it further. I tried writing a script to modify the cart, but i still get memory issue for that particular user
The site is setup on an amazon server, using a combination of redis, varnish, setup on nginx