T15 Ws + Precursor Tb = Still L79 Monsters?

Hello guys, please forgive me but, am I tripping? Am I doing something wrong here?

Normally, when I open any Endgame map node, even those clean nodes without any pre-buffs on them, if I put T15 Waystone, and a typical Precursor Tablet, it will open up an area that says Level 80 Monsters, right?

I vaguely recall that one of the previous patch or updates removed Precursor Tablet's ability to bump up the map's monster level by 1, not stack-able of course. But it got added back.

Am I to understand correctly:

T15 WS = L79 mobs
Right?

T15 WS + Irradiation = L80 mobs
If the map is not already irradiated, adding Precursor Tablet still L79 for me recently...

T15 WS + Overseer + Atlas Skill "Organised Forces" = L80 mobs
Still ok

T15 WS + Irradiation + Overseer + Atlas Skill "Organised Forces" = L80 mobs
Not stack-able I know, so not expecting L81

Help me please, to clear up my confusion...

Tier 15 + irradiate = monster level 80. You need to enter the map to see it though, so it may be a bug it doesn't display properly into the map device.

No, I went into the map. Not realising the information on the top right corner. I usually don't pay much attention as I'm confident putting Precursor Tablet will add one monster level through irradiation. Running L80 monsters maps usually. My setup is usually experience% tablets, Precursor + Breach + Delirium with T15 maxed pack size WS.

I only start to notice it when the items I pick up show Item Level 79. And then I test it out to confirm.

Or is it the particular tablet that is bugged?

I will find time to try inserting 3 precursors with T15 to see if it's still monster level 79 or 80.