Explanation
According to the Citrix Virtual Apps and Desktops 7 Deployment and Administration course, page 14 of Module 1: Architecture Overview, "Layer 3 mode is the default mode of operation for a Citrix ADC appliance.
In this mode, the appliance acts as a router and routes packets based on the destination IP address." Therefore, if the Citrix ADC receives packets that are destined for a MAC address owned by the Citrix ADC, but the destination IP address does not belong to the Citrix ADC, it will route the packets based on the destination IP address.