Deleted Project Group still appears in User assignment page

Steps to Replicate:

1. Add Project Group (Project Group Name: Testing1 , Project Group ID: Testing1 , Description: Test Project Group)
2. Delete added Project Group in [1]
3. Add User (Username: test , Full Name: test user , Email: test@test.com , password: test123 , confirm password: test123)
4. Click Submit button

Actual Result:
Noticed that the deleted Project Group in [2] still appears in the Continuum Resource Roles.

Expected Result:
Deleted Project Group must not appear in the Create User - Continuum Resource Roles.