An issue was discovered in Dalmann OCPP.Core before 1.3.0 for OCPP (Open Charge Point Protocol) for electric vehicles. It permits multiple transactions with the same connectorId and idTag, contrary to the expected ConcurrentTx status. This could result in critical transaction management and billing errors. NOTE: the vendor's perspective is "Imagine you've got two cars in your family and want to charge both in parallel on the same account/token? Why should that be rejected?"