Can't Create Assignee List on Issue Board

Description of the problem

I am trying to create an Assignee list on a sub-group level Issue Board with me as the assignee.

Which Group/Project (with full path) is experiencing the issue?

https://gitlab.com/groups/hyper-expanse/open-source/-/boards?=&label_name[]=technical-debt

Approximate date/time when the error occurred.

See HAR file.

Archive_18-06-19_11-55-02.har

Describe what you were doing right before the issue occurred.

Loaded up the Issue Board, navigated to the Add list option near the top right, and selected myself under the Assignee list.

Assignee Loading
Time tracking Loading