I have this in error log :
Notice: Undefined property: stdClass::$calc_value in XXX/components/com_virtuemart/views/invoice/tmpl/invoice_items.php on line 205
after
$sumRules[$rule->virtuemart_calc_id]->calc_kind = $rule->calc_kind;
adding
$sumRules[$rule->virtuemart_calc_id]->calc_value = $rule->calc_value;
fix it
Ignore it, if this is already fixed in new releases.
VM 3.0.9.4