Shop-for-Processwire: Error with product variations

[Pascal]

Hello,

I have a problem with the Shop-for-processwire module. Whenever I try to checkout with two variations of the same product in the shopping cart, I get this error:

Error: Exception: SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry 'example-product-1-1388' for key 3 (in /usr/local/etc/httpd/vhtdocs/reinka/pw/wire/core/Pages.php line 692)

#0 /usr/local/etc/httpd/vhtdocs/reinka/pw/wire/core/Pages.php(692): PDOStatement->execute()
#1 /usr/local/etc/httpd/vhtdocs/reinka/pw/wire/core/Pages.php(614): Pages->savePageQuery(Object(Page), Array)
#2 [internal function]: Pages->___save(Object(Page), Array)
#3 /usr/local/etc/httpd/vhtdocs/reinka/pw/wire/core/Wire.php(359): call_user_func_array(Array, Array)
#4 /usr/local/etc/httpd/vhtdocs/reinka/pw/wire/core/Wire.php(317): Wire->runHooks('save', Array)
#5 /usr/local/etc/httpd/vhtdocs/reinka/pw/wire/core/Page.php(1113): Wire->__call('save', Array)
#6 /usr/local/etc/httpd/vhtdocs/reinka/pw/wire/core/Page.php(1113): Pages->save(Object(Page), Array)
#7 /usr/local/etc/httpd/vhtdocs/reinka/pw/site/modules/Shop-for-ProcessWire-dev/ShoppingCheckout.module(651): Page->save()
#8 /usr/local/etc/httpd/vhtdocs/reinka/pw/site/module

This error message was shown because you are logged in as a Superuser. Error has been logged.

Does anyone have an idea what could be wrong here?