HexSys Group Quantity Attribute Plugin for Virtuemart 1.9.0

Perfect: thank you ...and again sorry for my wrong title for this post (maybe you will rename this topic).
Best regards,
Christian

Oh,
I am very sorry: I have two plugins from you and I did post my comment with the wrong Title: "HexSys Grouped Quantity Attribute Plugin for Virtuemart 1.9.1" it should be.
Here the file "quantity.php" contains the query in line 458.
Again sorry for my fault and...
...best regards,
Christian

Since the Joomla core update to version 3.8.10 there where problems with some payment plugins - for example with the PayPal plugin. When checking out, the message "1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'WHERE virtuemart_product_id = 1517' at line 3" came up. I did find four *.php files, containing the term "WHERE virtuemart_product_id". One file is "plugins/vmcustom/quantity/quantity.php". Because of this, I had the idea to deactivate the plugin ...and the error did not come up again and the payment did work without any problem.
Maybe you want to have a look, if there is a bug in your code.
Best regards,
Christian