Zombie Default Access Request Management Group

 Hi,

     Our SharePoint default control group "Asset Management Admins" is deleted several months ago. However, in the Access Requests Settings, the system still set it as the default owner group. And since that group is deleted and no member exists inside, no one is receiving any access request.

Below image is all the groups of the SP site. As you can see, goup "Asset Management Admins" does not exist.

     We did one experiment by creating a new control group having same group name as the deleted one. "Asset Management Admins". Then we assigned a new developer as its group member. However, new access request does not go to that developer's mail box, it goes to someone who was a member of the deleted group.

       What's the trouble of this issue?
      The field below the default admin group only allows filling one email address to receive access request. This causes trouble when that person is out-of-office, and add extra SP maintenance workload.

How to change the default access management group?
or how to thoroughly delete the zombie "Asset Management Admin" group?
Any advice/ workaround is welcome!

Warm Regards,
Xuan