Cart lost for logged in customer. Retrieved only after adding item

Question

We run a B2B webshop in Magento 2.3.5 and customers have to log in to be able to add items to the cart (Amasty Hide Price-module). However we are experiencing problems with disappearing carts:

1. Customer logs in
2. Customer places several items in cart.
3. Customer logs out / is logged out after some time.
4. Customer logs back in: cart is empty.
5. Customer places random item in cart: this item is in the cart together with the previously entered items.

I think it is a session / cookie issue but I can't quite figure out what / why this is happening and how to solve it. Any help would be greatly appreciated!

Answer 1

Since it's very difficult to pinpoint the problem without seeing the project, customizations, settings, etc, I think your best chance is to disable all your 3rd party modules and see if the problem is reproducing. Then take it one by one and re-enable your modules to see which is the culprit.

Good Luck!