Dell PowerEdge M1000e - TenGigaBit interface showing 40000 Mbit speed

I all,

I got the Aggregators configured as a stack. The uplinks I have configured are Te 0/52 and Te 1/52 and this 2 interfaces are part of a port-channel.

Te 0/52               Up     10000 Mbit Full   --
Te 1/52               Up     40000 Mbit Full   --

I cannot understand why a 10 gbps display a speed of 40 gbps. I have another cage with the same configuration working well and forming a port-channel with no problems.

Thanks in advance.

SR