pm2 not factoring in CPU% starting using multiprocessing in python

What's going wrong?

pm2 is not factoring in CPU% started using multiprocessing in python it only reports <100%, however when i do "top" i see 4 python processes with 100%, thus it seems it is not recording the processes starting using multiprocessing

How could we reproduce this issue?

from multiprocessing import Pool
from multiprocessing import cpu_count
from threading import Thread, Event
from functools import partial
import signal
import time

stop = Event()

def exit_chld(x, y):
    stop.set()

signal.signal(signal.SIGINT, exit_chld)

def f(seconds, ram, x):

    def exit_after_sleep():
        time.sleep(seconds)
        stop.set()

    Thread(target=exit_after_sleep).start()

    # stress RAM (Gb)
    a = 'c' * int(ram * 1024 * 1024 * 1024)

    # stress CPU
    while not stop.is_set():
        x*x


def stress(cpus, seconds, ram_gb):
    processes = cpu_count()
    print('----------------------------------')
    print('Running load on CPU(s)')
    print(f'Utilizing {cpus}/{processes} cores')
    print(f'Take up {ram_gb/cpus} GB RAM for each process')
    print('----------------------------------')
    pool = Pool(cpus)
    pool.map(partial(f, seconds, ram_gb/cpus), range(cpus))

if __name__ == "__main__":
    stress(4, 10, 2)

Supporting information

--- PM2 report ----------------------------------------------------------------
Date                 : Tue Nov 17 2020 13:57:50 GMT+0800 (Singapore Standard Time)
===============================================================================
--- Daemon -------------------------------------------------
pm2d version         : 4.4.0
node version         : 14.4.0
node path            : /usr/local/bin/pm2
argv                 : /usr/local/bin/node,/usr/local/lib/node_modules/pm2/lib/Daemon.js
argv0                : node
user                 : undefined
uid                  : 1000
gid                  : 1000
uptime               : 11min
===============================================================================
--- CLI ----------------------------------------------------
local pm2            : 4.4.0
node version         : 14.4.0
node path            : /usr/local/bin/pm2
argv                 : /usr/local/bin/node,/usr/local/bin/pm2,report
argv0                : node
user                 : undefined
uid                  : 1000
gid                  : 1000
===============================================================================
--- System info --------------------------------------------
arch                 : x64
platform             : linux
type                 : Linux
cpus                 : Intel(R) Core(TM) i7-6800K CPU @ 3.40GHz
cpus nb              : 12
freemem              : 29976203264
totalmem             : 134935105536
home                 : /home/node
===============================================================================

No repository file or test is identified in the issue. Start by running the supplied multiprocessing Python script under PM2 and compare its CPU report with top; done means PM2 reports CPU usage from the worker processes consistently with the system process view.