After the gizmo is detached, if you click on it to use it, such as translating the object with the translation widget, then the gizmo snaps back to the object in the Viewport.
Based off of [Link Removed] test execution history, I'm labeling this as a regression.
Repro:
Result:
Translation gizmo becomes detached from object in the Viewport as editor mode plugin is being use.
Expected:
Gizmos remain attached to objects in Viewport as editor mode plugin is being used.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-46543 in the post.