flowable:assignee="$INITIATOR" doesn't work


Can any one shed some light? I managed to make flowable:assignee="${INITIATOR}" works but flowable:assignee="$INITIATOR" doesn’t work, and this is generated automatically in explorer application if I select process initiator as task assignee.

I see in act_ru_task table the assignee is “$INITIATOR”

Best Regards,

(See https://github.com/flowable/flowable-engine/issues/534 where this discussion was done)