Can I work with an expired EAD while my 17-month extension is pending?
Yes. Your work authorization is automatically extended for up to 180 days while the 17-month STEM extension application is pending. There is not interim documentation of the extended authorization. If your employer needs information about what documents to collect as proof of extended work authorization, please refer to them to U.S. Citizenship and Immigration Services I-9 Central. For additional information, you can refer them to the optional practical training policy guidance issued by the Student and Exchange Visitor Program (under Immigration and Customs Enforcement). The relevant section is 8.4.2.