When SecureXL is enabled, interface information is saved in advance also for the other direction (in case the connection will be accelerated - i.e., if packet is 'Client-to-Server', then the same interface is saved for 'Server-to-Client' direction).
However, since interface information is saved, an interface mismatch can not occur. As a result, a QoS rule is not reclassified (which is per direction, unlike in FireWall rules) for the other direction.