Assign monitor to scom group doesnt work

Question

Hello Guys,
Hi Guys, need your help. I created group in SCOM and want to assign powershell script monitor to that group(MP Powershell cookdown). The script itself (created via Monitor->Create Monitor->Unit monitor) works when i assign in to class Windows Computers, but doesnt working for a group. Group have 2 members (windows computers) populated manually.
Seems script doesnt even run. I also created rollup monitor as per google advice, but still no success.

Im quite new in SCOM, might do something wrong. Any help would be very useful. Thanks in advance.