bluez is disconnecting devices 3 minutes after discovery as stated in "Device discovery" in this http://www.bluez.org/bluez-5-api-introduction-and-porting-guide/ , even though this signal - QLowEnergyController::connected() is triggering.

Why does bluez not recognize the devices as being connected and continuing to drop the connection?

This bug report - https://bugreports.qt.io/browse/QTBUG-44622 - was quite likely the same issue.

I attached the hcidump verbose log from create connection to disconnect.