Trying to copy custom fields from quote to invoice

Support
3

Invoice Plane 1.5.11
PHP 7.3
MySQL 8.0.21-12
Webserver Apache 2.2

Thanks for pointing me to the logs, forgot about those :see_no_evil:
There seems to be a duplicate entry invoice_id

DEBUG - 2021-02-13 13:34:10 --> File loaded: /var/www/ud08_441/html/invoiceplane/application/modules/custom_fields/models/Mdl_invoice_custom.php
ERROR - 2021-02-13 13:34:10 --> Query error: Duplicate entry '37-7' for key 'ip_invoice_custom.invoice_id' - Invalid query: UPDATE `ip_invoice_custom` SET `invoice_custom_fieldid` = '7'
WHERE `ip_invoice_custom`.`invoice_custom_id` = 102