One of the strangest things with visas is that the agency that authorizes a person to work (DHS/USCIS) is different and has different objectives from the agency

One of the strangest things with visas is that the agency that authorizes a person to work (DHS/USCIS) is different and has different objectives from the agency that issues the actual visas (DoS). With a valid USCIS work authorization a person already in the US can continue working legally, but the moment they step out of the country they need to apply for a visa with a US consulate (DHS). Applying for a visa with the DHS can take less than a week or more than 6 weeks (despite having all the correct documents). With the people I've spoken to, this causes a great deal of anxiety when travelling internationally. TL;DR: A work authorization document issued by one agency allows a person to maintain legal presence in the US. This is different from a visa -- a visa allows one to enter the country and is issued by another agency. The visa doesn't clearly specify what one can and cannot do while in the country.