Aql client overwhelmed by "WARN AEROSPIKE_ERR_TIMEOUT"

At ver - 3.9.1, dun was deprecated and services-alumni-reset introduced. so yes, 3.5.8, will not work

asinfo -v ‘dun:nodes=BB936F106CA0568’ where BB… is the nodeid that you want to remove.

what does asadm>info show? do you see the rogue node id?