I have an iPhone 7 and Resound Enzo aids. for some time now, all the way back to iOS 10, and made worse by iOS 11, I have had problems with the aids acting up when either incoming or outgoing call was made. The aids would show they are sending the audio to the aids, but then would switch to speaker, but no sound, then switch back to the aids, but not sound for maybe five seconds, then, most of the time, only connect with one aid or the other. I tried forcing the phone to always pair with the aids, but that did not fix the problem.
I have been reporting this to Apple since 11 came out. As usual it was a round about of blaming the aids, then the Resound app (the problem still happens with the built in aids control app). I got an email from them yesterday saying they believe they have fixed the problem with an iOS update that is still in beta. I have been using the beta for about 12 hours now, and it seems to have fixed it - at least, the time to answer and send the audio to the aids has been reduced quite a bit. So if you want to try it, here is the link. You will have to sign up for the beta program to do it.
Thank you for your email. We believe that the issue you are reporting has been addressed in the current version of iOS 11.4.1, which is available through our Public Beta program https://beta.apple.com/.
If you would like to try the new version, please Sign Up. Once you have signed up, you can go to the iOS tab and follow the instruction in the Get Started section to enroll your iOS device.
For more information on Accessibility at Apple, please visit: