Due to our current puppettization the secondary Icinga host is not monitored by Icinga. This is a know status since very long time and across the years it has caused various issues (T215848, T282019, ...), unexpected failures when following standard procedures, surprise in the operator and confusion due to the special nature of this set up.
The puppettization should be fixed to allow the secondary Icinga host to be monitored by the primary Icinga host like any other host and remove this special case.