Major Description
TSDescriptor::GetTSAdminProxy() and TSDescriptor::GetConsensusProxy() will return the same proxy instances over and over. Normally, this is a reasonable optimization. But suppose the IP address of the tserver changes (due to a DHCP lease expiring or some such). Now these methods will be returning unusable proxies, and there's no way to "reset" them.
Admittedly this scenario is a little contrived: if a tserver's IP address suddenly changes, a bunch of other stuff will break too. The tserver will probably need to be restarted (since it's bound to a socket whose address no longer exists), and consensus may be thoroughly wrecked due to built-in host/port assumptions (see KUDU-418).
An issue like this was reported by a user in Slack, who was running a master and tserver on the same box. The symptom was "half-open" communication between them: the tserver could heartbeat to the master, but the master could not send RPCs to the tserver.