Corrupted Nexus not spawning corrupted boss

I've completed several corrupted nexus maps recently, making sure to use a waystone with sufficient tier (3+ is where I'm at, used t6) and 6 mods, and no corrupted boss spawned. I also didn't receive any item giving me additional atlas passive points.

However, I did complete several unique maps that dropped items giving me passive points. So far, the amount of boss spawns/tomes I've missed is equivalent to the amount of unique maps/tomes I've acquired from other unique maps.

Is this intended design so that I don't ascend the tiers too quickly? If so, some UI indicator or other clarification is needed, because from my perspective it looks like a bug. I'm curious whether my nexus will correctly spawn a boss to put me back on the track of acquiring passive points.

same here,
I have a quest for 5+, did 6 or 7 and after beating the map boss, corrupted boss didnt spawn.
Worth noting is that I died once on boss and map was wiped.

btw. area around it is cleared, but didnt get boss and tome

got it second time, its for sure when You die on boss and kill him on next attempt. Map is wiped with the nexus boss probably.
I missed two tomes coz of that, can I have them back? :)

Same here.
Died once at map boss after clearing the Rare mobs.
Map reset to only kill boss and spawned me at waypoint near boss.
After killing the map boss, no corrupted boss spawned.

A workaround for minimum risk:
Open nexus with lowest tier 4 mod map with mostly Prefix Map modifiers.