under active examination 状态什么意思

今天收到了一个关于485 service request的回复，全文见下。重点是“we have reviewed the status of your case and found that it remains under active examination.” 和之前提到的"in line for processing"不同。不知道有没有有经验的同学指点迷经？

回复全文：
Based on your inquiry, we have reviewed the status of your case and found that it remains under active examination. This office acknowledges and realizes the inconvenience it may cause but it has been necessary in order to ensure thorough processing of your case. USCIS will notify you if any further information is needed from you or when a decision has been made. We hope this information is helpful to you.

485时间表(MSC2190XXXXXX)：
RD: 9/2020
Bio: 01/2021
Combo:01/2021
Transferred from NBC to TSC: 02/2021
"active examination": 04/2021

只要两个月有给你发过通知都算Active examination

请问楼主是以什么理由提交的485 service request？