Error running '/function start'

[EvilZoidYT]

Whenever i run '/function start' it shows a error 'Cannot give admin: Put Rubedo above another behaivor packs, Or Enabled All Expermentals!' Even though its the only enabled pack (single player) and every Expermentals are enable (except from villagers one and 1.21 one).

[TevimF]

i have same problem

[FunGamer111]

Same I thought I was doing something wrong but each time re installed it it did the same thing.