Commerce Module - Changing product in a display node makes the image revert back to default
Haven't found a solution to this, but a workaround I am using is to disable the 'enable as attribute' of both list fields, this makes it so there is only one list in the add to cart form. The list will have a option for each product that the node references, so if you have a lot of products, this can create a long list.

To do this, go to producttype > manage fields > edit (list field) and turn off 'enable this field to function as an attribute field on Add to Cart forms.' Then save. You have to do this for each list field. 

I will edit if I find a direct solution.