I don't think there is a reason to start worrying. They explicitly put it in your CAS status that the correspondence (apparently, fingerprint request) was sent to you on July 11, 2019. Give it another week or two, then go do fingerprints and you should be good. Fingerprint request is a routine procedure. I got the same update in CAS in September last year, waited a month for the mail to come. After I did fingerprints I had not heard from them for six months until late April when we were invited to take a test and the next day took the oath.
I have heard about cases when fingerprints were requested after the test and it means nothing (good or bad). They work on their own schedule and are not in a hurry as long as they meet 1 year deadline for processing. There are lot of thing they have to consider when scheduling folks for test and oath and most of them have nothing to do with your application. You still have plenty of time till September 19, 2019.