回複：請教明白人關於拿到綠卡馬上跳槽的疑問

This is what I remember by reading some other people's postings here:

If GC continues H1B's same position, you can change job one day after GC issued. In fact, in this situation, you can even change job after 485 has been pending for at least 180 days.

If GC is based on a pure offer, i.e., you start that position only after GC issued, you have to work a reasonable period of time, normally at least 6 months, to prove your original intention of permanently working for that employer was true.