Steps to reproduce:
- Go to "Site administration / Server / OAuth 2 services" and create a new dummy service called "IMS Global" (you can use incorrect values).
- In Site admin -> Badges -> Manage backpacks
- Create a new backpack with the following details :
- Save changes
- Edit the backpack you've just created.
Field "OAuth 2 services" has the selected "IMS Global" oAuth service.
Field "OAuth 2 services" is empty.
I've been able to reproduce it in 3.9 and master.