if you are in US and you got f1 after b1 then you are in f1. if you are outside us and coming inside then you use one of them and get in. you can’t hold both when inside us.

I had an f1 and came back to US to receive my EAD in the mail. when I flew that time, officer had put me on a b1 status despite seeing my f1 papers. he said all I needed to do was return to my home country with my EAD and customs and immigration officer will change my status

and apparently once I updated my school with my EAD approval, they terminated my f1

yes . that is my case. I have two visas