Agent plugins missing


We have deployed agents on 3100 servers (windows/linux) for the moment.
Today, I decided to apply a template (3 components) to ~1000 nodes, but only 50 app monitors are working.

For 950 nodes, the application monitor stays in "unknown" state, with "Initial poll in progress." output.

I have unmanage/remanage all application monitors, same issue. The agent state is "connected".
I edit the app monitor, launch a test, I had the message "Unable to schedule job on agent node ## required APM plugin is missing or not installed properly." Then if I wait 30 seconds (time for plugin installation) and test again, the application monitor is polling successfully.

So I check the plugins installed on the 950 nodes : I have 5 plugins installed whereas on working agent I have 17 plugins !

The agent is exactly the same, installed with the same way ; why I have such behaviour ? How to correct that ?

I'm a little bit upset pissed off, we bought Solarwinds licences 6 months ago and I'm facing ton of issues like that (despite my previous experience on the product), the solution is loosing credibility