OPT extension 要工作一定要有纸质的receipt嘛

维尼

没有官方答案，大概google下也没找到，只找到如果有receipt，但没有approve的状况下是否能继续工作。但是，同意沙发，你只要有receipt，那和是否收到那张纸其实是一样的，也就是你的资料已经备案了。所以，可以工作。这和是否收到EAD physical card 才能工作是不一样的。

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.

https://iss.washington.edu/employment/f1-employment/opt/stem-extension