Error with weight array key

-- HikaShop version -- : 4.6.2
-- Joomla version -- : 4.2.3
-- PHP version -- : 8.0
-- Error-message(debug-mod must be tuned on) -- : Warning: Undefined array key "gr" in L:\laragon\www\zoe4\administrator\components\com_hikashop\helpers\weight.php on line 42

Hello everyone,
I am migrating from version 3.10 to 4.2.3.
When I go to the checkout page an error is thrown:
Warning: Array key "gr" undefined in L:\laragon\www\zoe4\administrator\components\com_hikashop\helpers\weight.php at line 42

I had added the unit 'gr' in the configuration/advanced/weight symbols page, but the system replies that 'The weight unit "gr" is not in the list of possible units: mg,g,dag,kg,t,lb,oz,ozt,l,ml,cl'.
Has anything changed? This value comes from Joomla version 3.9, and I had no problems there.

Thank you
Davide

Hi
that's really funny cause the message has only now appeared. The same site, before the update to J4, did not show any error; I was able to select 'gr" from the dropdown menu in the product page (admin) and there were no error about that unit in the checkout process.

Anyway, I've created a mass action and changed all the values to the defalut 'g' unit.

Thank you for the reply!
Davide