I also have the an ACRA RDX 2017 purchased in October 2016.
I'm using iPhone 6
Since Apple update in October 2017 I think it was IOS 11.0.1
my radio phone display would only display the 1st., 4 phone numbers
Since than I have received about 4 updates and my phone.
My IPhone has IOS 11.1.2 operating system and still has the same problem.
I have disconnected my IPhone and reconnected to my radio. The radio would then display all
phone numbers until I would go to a different application on my Radio than Puff all phone contacts except with the 1st 4
contacts would disappear. I repeated this procedure about 4 times with the same results.
My car dealer and Acura says it's an issue with Apple and Apple says its an issue with Acura car radios
I believe it's a software issue with Apple.
There is no trouble with Android phones.
I paid a lot of money to have this type of Radio, and to have it not function properly is very disturbing
I'm hoping that Apple can resolve the issue soon.
Robert