While attempting my solo flawless earlier I encountered a glitch in the final boss room. The final Kell Echo in the big room didn't despawn after I cleared the last beam (first screenshot), and when I went into the DPS phase, the boss also never spawned in there (second screenshot). However, the vandal snipers in the DPS room eventually all spawned and I ended up dying to dark entropy (with no way of lowering the dark entropy stacks). Not gonna lie it was a pretty tilting way to fail a flawless run. Not sure if anyone else has encountered this before (or might know what causes this so I don't get -blam!- again in the future)?