I'm trying to create a homebrew cursed magic item.

one of the items modifiers is -2 and disadvantage on performance and persuasion rolls, setup in the homebrew as,

modifier type: bonus, modifier subtype: performance, ability score: CHA, fixed value: -2

this works correctly to a charisma score of 10 ( +0 then -2 when attuned) but then goes funny

CHA 12 (normal +1) attuned to cursed item +0

CHA 14 (normal +2) attuned to cursed item +2

CHA 16 (normal +3) attuned to cursed item +4

CHA 18 (normal +4) attuned to cursed item +6

CHA 20 (normal +5) attuned to cursed item +8

CHA 22 (normal +6) attuned to cursed item +10

You are adding a bonus of both Cha and of -2. Unselect Cha from the ability score dropdown.

interesting so possibly a double negative and yet applying disadvantage to both modifier sub-type and CHA in the same homebrew modifier does not have a flow on effect to all CHA abilities - only those two selected in the sub-type

i've fixed up my item, but i still think the calcs are wrong

also whats up with the override score not updating now (seperate issue - doesn't need an answer)

Quote from Stavros_Araatan >>

i've fixed up my item, but i still think the calcs are wrong

also whats up with the override score not updating now (seperate issue - doesn't need an answer)

 
I don’t mind. It’s probably the same issue, a stuck data cache.