今早收到USCIS一封奇怪邮件

一早收到这封邮件：

We are still reviewing your case and there are no updates at this time

We will notify you when your case status changes. We last took action on your case on May 31, 2019.

都不知道这是说的哪个Case，因为现在同时有3个Case在审

请教一下有人收到过这个邮件吗，这是啥意思