回複：回複：h1b extrension pending + 回美證入境會有問題嗎？

I asked my attorney the same question before. He suggested not to leave US until get the H1-B extension approved. Because when you come back with AP, the US Custom will issue you a new I-94 which number will be different from your H1-B's I-94 number. So you may have to leave US again to activate your H1-B's I-94 once you get approval.
This is the headache. You need to confirm with your attorney.