更新：
朋友已计划4月初回台湾，6月中回美，Visa stamp 到9/8。
正在准备h1b extension，刚刚律师对于出境的问题回复如下：
As you should be present in the US at the time the H-1B extension is filed wit
h the USCIS office, kindly schedule your travel accordingly. Please note that
as LCA can only be filed no more than 180 days before the start date, I will o
nly be able to submit your LCA in the next two days with it being certified ne
xt week. Alternatively, we may submit the H-1B extension after you return to t
he US in June.
Subject to that, as long as you have an existing valid H1B visa stamp on your
passport to re-enter the US, you may travel pending your H1B extension. Howeve
r, if your H1B extension is approved while you are outside the US, you must ha
ve your new H1B approval notice with you when you re-enter the US. Please also
bring with you your recent paystubs and/or employment verification letter.
1. 律师的意思是either出境前file或六月回来再file，但爬文板上看到在境外file似乎
可以走CN流程？
2. 因为曾出境过，回美后会不会得重送I129？
3. 五六月在台湾是留职停薪，对H1B extension 有任何不好的影响吗？
谢谢