H4 Extension expiry date does not match with the h1b expiry date. H1B is for 3 years while H4 is given for 2 years

My employer applied for H1B + H4 extenison on july 17 - Nebraska center. H1B in premium and was approved for 3 years until 2022. This is my first extension after 6th year.

H4 biometrics was given on Aug 8th and got case approved on Dec 3rd. But in the “I797C Notice of Action” form the expiry date is until 2021.

H4 passport expires on 2024.

Not sure why H4 expiry date didn’t match with H1B. Should I contact USCIS ? Please help.