Rebalance is not progressing, autofailover eventing node at 100% CPU

Build : 5.5.0-2915

While running centos longitivity we add a KV node and then rebalance.
Ns_server is trying to autofailover eventing node that is at 100% CPU, since the heartbeat will not be available.
Since there is a rebalance in progress, the rebalance is stuck with simply trying to autofailover the eventing node.

Following error in the log 

Could not automatically fail over nodes (['ns_1@172.23.96.209']). Rebalance is running. (repeated 2 times)

supportal link : https://supportal.couchbase.com/snapshot/9d575cf4cbd041d49772f53fc1a5d1c3::2