standby is not following after registering

[ahoiahoi]

Greetings

We use repmgr 5.2 with postgres 11 on rhel7 with 2 nodes

In one environment, after standby clone/standby register the node is automatically attached eg "following".
On another environment, the standby is not registered:

$ /usr/pgsql-11/bin/repmgr -f /var/lib/pgsql/11/repmgr.conf cluster show --compact
WARNING: node "node2" not found in "pg_stat_replication"
WARNING: following issues were detected
  - node "node2" (ID: 2) is not attached to its upstream node "node1" (ID: 1)

 ID | Name                  | Role    | Status    | Upstream                | Location | Prio. | TLI
----+-----------------------+---------+-----------+-------------------------+----------+-------+-----
 1  | node1 | primary | * running |                         | default  | 100   | 3
 2  | node2 | standby |   running | ! node1 | default  | 100   | 3

when executing "standby follow" all is fine - but I am surprised why it is necessary in the one enviroment while not in the other.

Thanks in advance