Legion Monolith fails to disappear after Legion Encounter (Bug Report #1,564,756,015)

Was running a T16 map through Kirac, and a random (not associated with either the map mods nor mission requirements) Legion Encounter was present. I ran it, and the crystal at the center never disappeared, even after every Legion monster was killed. (and the music returned to normal)

• Bug Report ID: 1,564,756,015.
  
  
• Reproduction: Exact reproducibility may be hard, but for what it was worth, the map was a T16 Kirac mission to complete a (Rog) Expedition encounter. There was also a Delirium Mirror & Ultimatum encounter present. The Delirium & Expedition encounters were completed before starting the Legion Encounter, and then after the legion encounter the Ultimatum one was done. At no point were any two of those encounters active at the same time; they were all done in-sequence.
  
  Worth noting that the Delirium mist faded, but an unusually long amount of time was taken before the reward meters disappeared & the rewards dropped; at least 15 seconds longer than typical. Again, this happened before the Expedition Encounter (and then Legion Encounter) were started. Each encounter was allowed to 100% finish everything before the next one was started.
  
  
• Screenshot: Attached is a screenshot showing the anomalous behavior: the Legion Monolith Crystal is sitting there floating (as it normally does during the "freeze countdown" stage of the encounter) in spite of the encounter clearly being over.