This MTU check is to confirm failover
If you have jumbo frames configured, the installer will take care of configuring it within the UCS domain and within ESXi
However, the upstream switch needs to also be configured for jumbo frames and all VLANs need to be present on the pair of upstream switches so that the installer can perform the failover testing
Contact the Cisco TAC frontline to open a case and engage someone from TAC to assist with troubleshooting: Cisco Worldwide Contacts
