Cannot access offset of type stdClass in isset or empty on save product

-- HikaShop version -- : 6.1.0
-- Joomla version -- : 5.4.0
-- PHP version -- : 8.3.27
-- Browser(s) name and version -- : Chrome
-- Error-message(debug-mod must be tuned on) -- : Cannot access offset of type stdClass in isset or empty

Hi,
When I add a new product and I select one or more characteristics I get this error on save

Cannot access offset of type stdClass in isset or empty

When I add a product without characteristics and save it's ok. If I add the characteristics after I can also save without problems.

Is this a bug?

I have it on two sites (same php, hika and Joomla versions)

With kind regards,
Rachel Walraven

Hi Nicolas,

Thank you for your quick response. I've updatet Hika tot 6.1.1. The issue is still there.
So I turned on debugging and got these for the first lines

1 () JROOT/plugins/hikashop/massaction_product/massaction_product.php:305
2 plgHikashopMassaction_product->onProcessProductMassFiltercharacteristicColumn() JROOT/libraries/src/Plugin/CMSPlugin.php:320
3 Joomla\CMS\Plugin\CMSPlugin->Joomla\CMS\Plugin\{closure}() JROOT/libraries/vendor/joomla/event/src/Dispatcher.php:454
4 Joomla\Event\Dispatcher->dispatch() JROOT/libraries/src/Application/EventAware.php:111

I've attached a screenshot of the whole list.

With kind regards,
Rachel Walraven