This is an old thread, but I think I have a fix if others are still facing this!
First off, this issue is not specific to phone models, but Android in general. Sort of. I'm using an HTC One M8 Google Play Edition on AT&T and the stock EQ presented the same absurdly frustrating random shut-off. I tried installing a few different players and EQs to no real avail.
I then went through my Apps manager to start deleting those, and stumbled across a built-in "app" that didn't show on my apps list called MusicFX--the same plug-in that drives the stock EQ. After uninstalling all the 3rd party stuff, I went to the Play Store and searched for MusicFX and found this:
https://forums.androidcentral.com/e...tails?id=com.lifevibes.musicfx&token=jtiuD7Ez
I installed it (so it now shows up in my App list) and the EQ works
perfectly! You still have to access the EQ through the settings of whatever music player you use, as opening the "app" will just tell you it's a plug-in. Either way, I've thrown a few different scenarios at it:
1. Unplugging and plugging in headphones
2. While headphones are plugged in, activate my A2DP headset
3. Plug in headphones while music playing through phone speaker
4. Switching tracks and albums
a. Within Play Music app
b. With Play Music notification controls
c. With Play Music lock screen controls
d. With bluetooth remote
e. With wired headset in-line controls
I'm happy to report the EQ stayed on and kept my settings throughout ALL OF IT. Not even a hiccup. Booyah!
Hope this works for you guys, too!