The root server should not advertize a relay auto selection group that clients will try to use. The root should specifically advertize a relay selection group of some kind that either no clients use at all, or only those that should use the root look for (top level relays)
Something like:
ROOT
Clients should not use a relay auto selection group setting of just “*” unless that is the very last entry.
Something like:
MyLocationRelays;NextLevelUp;DMZ;Failover;*