I use dual connection to connect the headphone to a Windows 10 PC and my iPhone Xr iOS 7.4.1. The headphone is on version 58 which is the latest version. So the problem is as follows.

When I'm playing music from PC (usually from foobar2000 but occasionally from Spotify) and then my phone gets a notification, the music won't resume afterwards. Even if I press the physical play button on the headphone, it will start playing music from my phone instead of resuming the playback from the PC like it's supposed to. 

It does this whether I'm playing music from foobar2000, Spotify, and even WMP. I've tested it. I've tried resetting the headphone and removed it from both my PC and phone and re-paired them but it still does the same thing. I've contacted customer support but they just said it's not supposed to do that and offered no help at all. Not even a troubleshooting guide. Any idea how to fix it?

TLDR headphone won't resume music playback from PC after notification from phone.