For my understanding, this leave means leave company A permanently, never return.
1.But how about this scenario, I leave company A only for a period of time, say, 3-4 years, and tell company A plz don’t withdraw I-140, when PD is current for that I-140, I rejoin the company A again, and file I-485, is that I-140 is still valid (can I still get GC through company A?)
-Yes, that will be fine.
2.Further more, in company A, after filing I-485, but when < 180 days, I end a client company’s project (say that project only 3 months), based on company A’s policy, they will terminate employment relationship with me, but after a short period of client project(/job) searching, I get project again and rejoin company A, in this scenario, is there any issue for that GC approval?
-No problem unless USCIS makes a decision on your I-485 during this period of time when your I-485 pending is < 180 days.