What does that mean?

Have you ever experienced that can not send offer letter due to HR work at home yesterday and today, but need me to start to work on Thursday? During interview said need two weeks notice, but now all of sudden, told me the big boss would travel overseas for a month, that's why need me come in on Thursday. Told me it would be no problem to transfer H1B, but also asked me can I work while it is pending?

Would it be some tricks in there?