Hi,

When using my iPhone 6S with my car's bluetooth entertainment system (a Kia Cerato), callers hear their own voice and find it very distracting when talking to me.

This issue never occurred with my (previous) iPhone 5S, and does not occur with my girlfriend's iPhone 6S.  So I have ruled out a volume issue (as in callers can hear themselves via the car's speakers).

Does anyone have any ideas as to what might be causing the issue or what the fix is?  I've done a bit of a Google on the issue and haven't found anything useful.

Cheers.