custom product ignores the maximum purchase

[shopwareBot]

Used Shopware Version: 6.5.8.2

Description: Currently, there may be a situation where if a custom product template is assigned to a product that also has a maximum quantity set, unexpected behavior occurs.

Alternatively, another error may occur where the setting of the maximum allowed quantity takes effect. Then, if the contents are deleted from the shopping cart and added back again, this error message appears.

"CHECKOUT__CART_LINEITEM_NOT_STACKABLE"

Steps to reproduce:

1. Set up a custom product and assign it to a product.
2. Set a maximum quantity for the product.
3. Test in the frontend.

Expected result: All settings take effect correctly.

Actual result: The maximum quantity is ignored, or the error appears.

[shopware-issue-bot[bot]]

We found the following existing issues which may help or are related to your topic:

• Max Order quantity on product level
• 'Max Order Quantity' cannot displayed on Storefront, if 'Purchase Steps' is greater than one
• Products: Max. order quantity cannot be deleted
• Product quantity limit not working correctly
• show hint about cart.maxQuantity at products minPurchase
• Max. order quantity = 0 | add to cart button is still usable in listing
• Custom Products overwrites Essential characteristics in the shopping cart
• Bad performance on high max. order quantity
• Incorrect display in the shopping basket if custom products are not recognised

[shopwareBot]

[public] Automated response: This issue is linked to the internal issue https://shopware.atlassian.net/browse/CUS-685.

[created from CUS-685, comment 484949]