Monitoring results not reported to Foreman

** Problem After upgrading to Salt 2018 I do not receive Monitoring results in Foreman Monitoring tab for newly created machines.

The reports still come in for servers I created before the upgrade but not for the machines I created after the upgrade.

This is visible in the production log of foreman, as there are no POST entries for server117 but for the other ones:

2018-08-02T16:34:27 0f72f7a1 [app] [I] Started POST "/api/monitoring_results" for 10.35.147.116 at 2018-                                                                             08-02 16:34:27 +0200
2018-08-02T16:34:27 0f72f7a1 [app] [I] Processing by Api::V2::MonitoringResultsController#create as JSON
2018-08-02T16:34:27 0f72f7a1 [app] [I]   Parameters: {"result"=>1.0, "host"=>"server1100", "service"=>"m                                                                             yRAMImpl", "timestamp"=>1533220466.687533, "apiv"=>"v2", "monitoring_result"=>{"service"=>"myRAMImpl", "                                                                             result"=>1.0, "timestamp"=>1533220466.687533}}

Any idea where I could check to find the culprit?

** Setup Foreman: 1.17.1 Monitoring plugin: 1.0.1 ruby-smart-proxy-monitoring/plugins,plugins,now 0.1.1-1 all [installed]

icinga2 - The Icinga 2 network monitoring daemon (version: r2.9.0-1)

Copyright (c) 2012-2018 Icinga Development Team (https://www.icinga.com/)
License GPLv2+: GNU GPL version 2 or later <http://gnu.org/licenses/gpl2.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Application information:
  Installation root: /usr
  Sysconf directory: /etc
  Run directory: /run
  Local state directory: /var
  Package data directory: /usr/share/icinga2
  State path: /var/lib/icinga2/icinga2.state
  Modified attributes path: /var/lib/icinga2/modified-attributes.conf
  Objects path: /var/cache/icinga2/icinga2.debug
  Vars path: /var/cache/icinga2/icinga2.vars
  PID path: /run/icinga2/icinga2.pid

System information:
  Platform: Ubuntu
  Platform version: 18.04 LTS (Bionic Beaver)
  Kernel: Linux
  Kernel version: 4.15.0-29-generic
  Architecture: x86_64

Build information:
  Compiler: GNU 7.3.0
  Build host: f383d9b8a88f

theforeman / smart_proxy_monitoring

Monitoring results not reported to Foreman #21