Duplicate entry oc_product_to_store

Hi,
When I copy a product in Opencart 2.1.0.2 (Products) I get a duplicate key error because the product_id does not get incremented. I tried setting this column to auto-increment but that didn't work. Is there a fix for this?
Thanks

Notice: Error: Duplicate entry '1658-0' for key 'PRIMARY'
Error No: 1062
INSERT INTO oc_product_to_store SET product_id = '1658', store_id = '0' in opencart2/system/library/db/mysqli.php on line 41Warning: Cannot modify header information - headers already sent by (output started at opencart2/admin/index.php:84) in opencart2/system/library/response.php on line 12