Warning: Undefined array key “b2bking_customergroup”

I get this warning for each user:

Warning: Undefined array key "b2bking_customergroup" in wp-content/plugins/b2bking-wholesale-for-woocommerce/admin/class-b2bking-admin.php on line 4506

It happens when a user is created by another way than manually, for example by an import plugin.

Is it possible that you fix it? You can just check that $_POST[‘b2bking_customergroup’] exists on line 4506.