In our BLE peripheral using DA14581, upon connection the peripheral sends an Exchange MTU Request and typically receives an Exchange MTU Response. We have run across iOS devices which following the DA14581 sending the Exchange MTU Request, the iOS device sends an Exchange MTU Request and the DA14581 sends an Exchange MTU Response. At this point the iOS device sends a Write Request to a DA14581 characteristic. The DA14581 sends a Write Response and would typically then send an Indication. In the case where the exchange MTU sequence occurs as described no indication is ever sent even though the two sides have successfully negotiated the MTU.

Is the lack of receiving the Exchange MTU Response in this instance keeping the DA14581 in a state where it does not perform indications?

Thanks for your help.