Capability "Unassigned Backlog" is empty even though Capabilities exist with no PI assigned

Issue Summary

Capability "Unassigned Backlog" is empty despite there being Capabilities without a PI assigned

Steps to Reproduce

1. Create new Capability, assign to Program, but do not assign to a Program Increment
2. Go to Capability Backlog
3. Set T1 configuration with the Program in question and at least one PI
4. Click the 'Unassigned Backlog' button

Expected Results

The capability just created should display in Unassigned Backlog

Actual Results

Unassigned Backlog is empty

NOTE: Same problem seen with Portfolio Epic backlog

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available