Hi, I´m having a similar issue in my setup that uses a different switch model and version (WS-C3650-48PD / Version 16.3.6)
In this scenario, an IP Phone 8851 connected to the catalyst switch is padding the Ethernet frame for an 2833 RTP event packet with 2 extra bytes with apparently random values (e.g. d5d5), what seems not entirely correct as the Ethernet padding should be 00 00 afaik. In any case, after the switch I can see those bytes are decoded by wireshark as VSS-monitoring ethernet trailer.
Do you know if the bug described in this TAC case for Cisco Catalyst 9500H Series Switches could be part of the Catalyst 3650 series as well and what the fix/workaround may be in this case?
Are you also aware of a bug in some 8851 HW versions regarding the Ethernet padding with values different to 0?
Thanks