Github user mcgilman commented on the issue:
https://github.com/apache/nifi/pull/2276
@sbouchex This is a great catch and thanks for the contribution! Reviewing
the code it appears that the runStatus was moved into the status snapshot
likely during the 0.x -> 1.x transtion. This value is being set currently and
is what the UI uses to render the status. However, with the runStatus still
being available in the status it makes sense to populate it as well. I'll
continue the review by commenting on the code...
---