Nightmare Maps inaccessible in Standard

You can't access Nightmare Maps, Reliquary Keys and probably other stuff too. Please fix GGG, thank you!

can confirm. an old t17->nightmare, or a new raw drop won't work at all. my friend that plays on ps5 can't use reliquary keys either

Same here. Neither old nor new Nightmare maps work in standard. You just can't insert them into the Map device to open, it won't let you.

EDIT: Found the fix!
You have to run the progression Atlas Bosses again (Searing, Eater, Maven, Sirus, Cortex, Elder, etc.) to open up the Nightmare Map slot behind them.

Yes, I know, you already have unlocked those Atlas point. But you have to run them again.

(Also, although GGG said you'd only have to run x1 Nightmare map to unlock the x5 passive Atlas points in standard, it doesn't work. At least not for me. I had to run each x5 Nightmare Maps individually)