Thanks for your feebacks. I do my best seriously to communicate what I can !

We note this issue on very busy server only, it will be hard to remove all modules on such busy server, and reconfig all, but not impossible. Anoop is on the case on smallest servers, and succeed to see the issue at small scale, he will troubleshoot with sometimes...

Yes, 1 of the 3rd party module is leaking memory for sure, no doubt about this for me.

ps alx | grep nginx" after restarting nginx
This gives 1.16% as usual
+ 1 more reload, we get around 2.24%
+ more 100's more reloads, we gradually get to 2.58%