prestashop 1.7 PrestaShop 1.7 adds random product to shopping cart

[wim vos]

When a gest adds a product to a schopping cart, Prestashop adds another random product to the cart.
Making that two products instead of one.
My customers understandably do not like that very much.
Resulting in abandoned carts.

Use the custom theme.
We have imported data from an old version of oscommerce.
customers, orders, about 3000 products, etc.
Most likely old shopping carts came with the transfer as well.

A search revealed a similar problem in topic/146717-presta-adds-a-random-product-to-new-order/
This is from 2011 and does not seem to apply to PrestaShop 1.7.
Looking in the database in ps-orders maximum id_order is: 1952

ps_order_detail shows:
id_order_detail    id_order    id_order_invoice
4682            1952        0    
4681            1952        0    
4680            1952        0
4679            1952        0
4678            1952        0
4677            1951        350
4676            1951        350    

Very much appreciate a hint in the right direction of solving this
 

Edited December 9, 2017 by wim vos
language (see edit history)

[wim vos]

Does nobody know the answer or am I posting in the wrong forum?...

Just let phpadmin repair/ optimise the database, but without joy.

Someone Please?

Edited December 18, 2017 by wim vos (see edit history)