I submit application (concurrent) on June 28, I already receive EAD and travel approved, i140 approved on July 28. However, my green card didn't receive ref and it transfer to national benefit center. My question are

a. Is that something wrong? something will significant delay my green card application

b. Next 3 month, it will be 6 months for pending on i485 and i140 approved. I can trigger AC21 and transfer. If after transfer, my i485 is denied. Can new employer submit for my i485 or appeal? i140 already approve by old company? Is that possible? Is there any solution if I transfer and after transfer my i485 deniel?