Not to be trite, but BPDU guard means the switch is seeing a spanning-tree BPDU come in on a port where none is expected. Your switch is likely configured with "spanning-tree portfast bpduguard default". For trunk ports, you may also have "spanning-tree portfast trunk", unless you have bpduguard per-port.
Are you seeing BPDUguard on ALL VLANs of the trunk port, or just certain VLANs? This would help you determine the exact cause:
show spann int TeX/Y/Z
Are you running VS in active-active bridge mode? This will emit 802.1d frames. VMACs won't cause BPDUguard, tho.
You can see details of spanning-tree on the port with "show spann int TeX/Y/Z details" to get some idea of what's coming into the port. If you have a port-channel, and you're only seeing BPDUguard on a single port of the bundle, then you have a port configuration mismatch.
If, for some reason you NEED to have BPDUs through this port, you can still allow them but not allow a lower priority BPDU:
int TeX/Y/Z
spanning-tree bpduguard disable
spanning-tree guard root
If you are using Active/Active Bridge mode VS, then this is the config you on your port. Root guard will prevent your spanning tree topology from pivoting towards a new lower priority, or lower bridge ID, root bridge. Which would be terrible
You *DO* want to take care of your spanning tree topology, however. I presume you understand STP enough to set your preferred primary and secondary root bridges on your network. Make sure your root is where you think it is.
Lemme know if you have any questions with it.
Good luck!
