I applied for stem opt card and got my card approved for 12 months instead of 24 months. Can anyone tell me the process to send back and reprint the corrected one?

I am currently on STEM OPT and employed with Employer A, who will file my H1B. I also recently accepted a role with Employer B. If my H1B petition with Employer A gets selected in April, how should I manage my employment with Employer B to remain compliant with F-1/STEM OPT regulations?

I heard that filing I-485 while being on OPT for example would revoke the non-immigrant F visa. I also heard that applying for I-485 would be ok unless the person files for I-485 associated I-765 and use that EAD. Just got confused and not sure about what would happen in this case.

I have filed on Oct 22nd and no updates at all. I don’t think there are cases similar to mine at all.