Indicates that the stack has split into two distinct stacks which means that each stack may end up with its own master temporarily until the stack is rejoined. This is possibly different from the stackMemberUnitFailed trap, which indicates only a single unit failure. This trap indicates that the master has lost track of part of the stack membership so that the other units may elect their own master. The dellTrapSource should indicate the master unit ID and the dellTrapInfo should identify the units that are split from the main stack.