The ad_impression event does not receive its source from the admob platform

Hi everyone,

I'm having the following problem, anyone who knows please help me.
We have a mobile game app that uses MAX mediation.
In MAX mediation we have ad units Inter, reward, appopen
We also use admob's collapads.
Currently, the ad_impression event only receives information from MAX but not from ADMOB, so the revenue information is missing.
I don't know how to fix it now, please help me.
Thank you very much!