Central Board Of Secondary Education [CBSE] — MY grades in memo

Today i.e., 6-7-2023 I received my 10th memo. when I looked in my memo, I was shocked to see my grades given haphazardly.
like in social I got 82 marks so I should get a2 right. but in my memo, I got b2. like this every grade in my memo is haphazardly given. It is creating a mess in my Carrer. pls look into it.