Nexus 7k VPC peer link mixed modules

Just so everybody knows, when the documentation over at says you can’t mix modules for VPC links they only say that you can’t mix F and M series.  What they don’t tell you is that you can’t mix M modules either.  We recently had an M1 series module fail and tried to move one of the port-channel links to an M2 module, the command fails when you try to add the interface to the channel-group.

Why isn’t that in the same document that says you can’t mix F and M series?  I have no idea.  TAC told me that you can mix M modules for regular port-channels, but the VPC peer-link requires that they be the same model.