Hi Thomas !
Thanks for your answer and you are right about my if statement that was wrong.
But unfortunately, even without the 'apm.addFilter...' function call, there is still no body in my HTTP POST requests, and no user/custom context or tags in any of my requests. No errors appear in my logs.
Btw im using nodejs 8.9.4, hapijs 16.4.3 and elastic-apm-node 2.0.1
Thanks again for your help 
Have a good day 