vCMP guests logs "Skipping heartbeat check on peer slot X: Slot is DOWN."

We have 2 VIPRION C2400 chassis with 2 B2250 blades in each.

 

On these we have vCMP guests in several active/standby clusters (DSC) between the 2 chassis.

 

Device-group-A:guest1/chassis1,guest1/chassis2 , Device-group-B:guest2/chassis1,guest2/chassis2 , and so on.

 

Recently we found that some (not all) of these clusters (DSC) is reporting/logging:

 

"info clusterd: Skipping heartbeat check on peer slot X: Slot is DOWN".

 

X is every slot except the one the actual vCMP itself is running on.

 

2 slots (3-4) in each chassis is empty, so yes , one could say that they are "DOWN".

 

But the second installed blade (slot 1 or slot 2) is not DOWN - it is up and running with vCMP guests, so we dont understand why it is reported Down.

 

Neither do we understand why we have this behavior on some of our clusters (DSC), but not all.

 

We've tried to compare them, but havent found differences who can explain it.

 

Does any of the experts in here have a clue of what this can be?

 

PS!

 

Big IP version is 12.1.2 HF1 on both chassis (hypervisor) and all vCMP guests.