AD Manager Technician access issue

Hi Team, I want to bring to your notice that I am facing a weird issue and want to check with you guys that if this is a bug in the build or this is how it is made up. I am Superadmin and I have provided access to one of my Technicians who should be able to create the user in the specific OU and should only see the groups present in the selected OU. OU structure is like "one parent and 4 Child OU" When we are providing access to the Parent OU it also shows up the groups present in the Child OU which is not even selected. When we only select the child OU then it doesn't show the groups under it. My issue is why the groups present inside the child ou are shown even if the child ou is not even selected. Prompt Response will be appreciated! :)