Issue reference changes when adding to epic

Steps to reproduce

• enable epic_trees feature flag (#10795 (closed))
• open epic page
• add issue

What is the current bug behavior?

Issue is shown with full reference (group name + project name) but after page-reload only ID is shown.

Screen_Recording_2019-11-19_at_11.35.54

What is the expected correct behavior?

Reference is consistent.