A migration from an image mode volume will use the source storage pool and the source storage pool assumes the combined state of the image mode MDisk and the storage pool. If the online or offline states of the image mode MDisk and the storage pool are different on different nodes, the source volume might go offline or all of the volumes in the source storage pool might go offline.
For each node, note the online or offline states of the source volume and the source storage pool. If one entity is online and the other is offline, bring online whichever is offline. Taking the online entity offline is not recommended because other volumes might go offline.