Visa duration vs validity of stay

Hello,

Has anyone experienced this case where the visa duration is longer than validity of stay? In my case, I got a multi entry visa valid from 15/1/2025 till 26/1/2025, yet the duration of stay is 90 days. I don't get how i got a duration of 90 days but the validity is 12 days as I know it is the other way around usually where the validity is 6 months and the duration is 3 months. Does anyone know how this works?