NPC proficiency bonus

[Zacchaeus]

Can you post a screenshot of your NPC and it's spellcasting ability trait.

[IngeRasch]

1.PNG
2.PNG

[esmdev]

You can override the automatic calculation of the spell save by including in the spellcasting trait the following:

"The <name> is a xth level spellcaster who uses intelligent as their spellcasting ability (+x to hit with spell attacks, spell save DC x)". Replace the x's with the correct number.

EDIT: also if you have the CR correct and the correct ability score then the spell attacks and DC should work out automatically.

You might want to edit the quote to change intelligent to intelligence to avoid confusion.

[Zacchaeus]

1.PNG
2.PNG

I don't know then. You don't show the Wisdom stat so I have to assume their Wisdom is 20?

Here's a quick test character I did with Wis of 18 and a CR of 1. As you can see the save DC is correct.

[Zacchaeus]

You might want to edit the quote to change intelligent to intelligence to avoid confusion.

Well spotted. Done.

[IngeRasch]

I don't know then. You don't show the Wisdom stat so I have to assume their Wisdom is 20?

Here's a quick test character I did with Wis of 18 and a CR of 1. As you can see the save DC is correct.

Apologies, Wisdom is 16 (+3).

I had just finished writing a beefy reply on the underlying math being wrong. It just turns out I'm the problem in the equation
Spell DC is supposed to be 8 + modifier + proficiency, not 10 + modifier + proficiency.

It was working exacly as it should this whole time.

Here's my wording for anyone struggling:
Kethra is a 2nd-level spellcaster. Her spellcasting ability is Wisdom. She has the following druid spells prepared:
Cantrips (at will): druidcraft, poison Spray
1st level (3 slots): cure wounds, entangle