Hi guys,
sorry for late response.
what happened is actually correct behavior. And as you can see below it's really caused by installing NPM 10.5 first.
Both NPM 10.5 and IPAM 4.0 uses new generation of Orion Core Services. For that reason, IPAM has to carry "additional poller" or "poller" installation pack that needs to be deployed on all existing APs of your SolarWinds modules. The only reason is to upgrade Orion Core Services so all modules may use latest version. If you would not upgrade it would probably stopped working.
What you've done is you installed NPM 10.5 and AP first and then apply IPAM installation. But because APs were already updated you got that message that it's already there. But this state is fully OK and installation should work correctly.
let me know if I missed something in your scenario.
thanks,
Michal