redundant CMC and networking issues

Hi,

We have a M1000e with a pair of redundant CMCs, each connected to separate management switchs, which in turn are connected to the core switch. When the CMC in slot 1 is active, then it seems that we can connect to the CMC and all the iDracs, and out-of-band chassis switch management interfaces, as expected. But when we fail over to the CMC in slot-2 we lose connectivity to most of the iDracs and oob switch interfaces. Monitoring the CMC-slot-2 uplink port on the switch, we can see it learning the MAC addresses of the devices that work, but no responses for the un-responsive devices - this persists for far longer than any ARP or CAM aging.

The CMCs were running 4.30 firmware, but we have since upgraded them to the latest 4.45, and still see the problem.

Could there be a problem with the devices failing over to secondary management fabric? There doesn't seem to be any documentation on the subject, so I was guessing that it should 'just work', but then you have the issue of the upstream switches learning the new path to the new live port.

Anyone else seen this?

Oli