Core issue
The EtherChannel provides incremental trunk speeds between Fast Ethernet, Gigabit Ethernet, and 10 Gigabit Ethernet. EtherChannel combines multiple Fast Ethernet up to 800 Mbps, Gigabit Ethernet up to 8 Gbps, and 10 Gigabit Ethernets up to 80 Gbps.
This is a normal behaviour as trunk ports are part of multiple VLANS, not just a single VLAN. Any port configured for access vlan shows up under show vlan. Trunk ports never show up under any VLANs.
Resolution
These are the reasons for this behavior:
Trunk ports that are connected to other device do not appear in the output of the show vlan command.
Trunk ports that are not connected appear by default in vlan 1 and also appear in the output of the show vlan.
Ports on an EtherChannel do not show up in the show vlan command output. In other words, when the port channel interface is set up to trunk and carries more than one VLAN, the ports set up to channel do not show up in the VLAN database as active ports.
