I can confirm this can be observed on any mobile Android project (not just VR) with Mobile HDR enabled. A simple scene will be unreasonably slow on the device with profiler showing the time is sunk in Present Time. This can be seen even on UE4 mobile starter projects. At the same time, iOS builds work just fine with Mobile HDR, as long as your scene is not too complex.
I think this was not an issue several versions ago (around 4.10?), but then something was introduced that started to cause this problem.