For all I know this is intended, but when I get an osprix echo the difficulty is way beyond any of the others.
I play melee hardcore, so am pretty aware of relative threat and mortal dangers. I am lvl 96, playing through corruption 100 empowered echos. I can cruise through most anything without coming close to dying, including all the timeline and echo bosses.
For some reason, the osprix zealots, embermages, covenants of dominion, etc when all together require a ton of kiting, fleeing, waiting for cooldowns, etc, when no other tribe of enemies forces my build to fall back on these unsatisfying tactics. The disparity in difficulty based on which set of enemies you get (IE, osprix vs all others) strikes me as stark.