THE REAL SOLUTION to this really frustrating issue for me (and a really stupid workaround) was exactly what jpathak mentioned earlier. I tried the remove/add widget and unpair/pair Powerbeats 3 (an APPLE DEVICE for everyone saying it’s because it’s a 3rd party device. C’mon, seriously? The only reason they are having this problem is because it was showing up BEFORE and NOW post-os11 it isn’t.) and none of those solutions worked.
To elaborate on jpathak’s post, the issue lies in the placement/order of the widget. For me, it needs to be placed in an even-numbered slot for every device to show properly. That means 2nd, 4th, etc... from the top. So I’m relieved to have my battery level back, but....
(This is more for Apple’s devs) Something else I noticed is that when my battery widget was in an odd-numbered spot, my Powerbeats3 wasn’t showing up, but I turned my Powerbeats3 off, it would make my Apple Watch disappear. Also, even though my Powerbeats wouldn’t show up but it was on and connected, an empty slot would appear in the widget as if that’s where the Powerbeats is supposed to show.........
SO my conclusion as a non-CS major is that this is simply a cosmetic issue and not a serious technical problem. Meaning, easy to fix. C’mon Apple, you are spitting out updates every week and can’t fix this. Why is this a problem? Because as a customer who bought a $200 or something pair of headphones, I have to risk suddenly losing music on a run or workout (playing off my Apple Watch) because I had to physically plug my headphones into my iMac to check battery level. At least my Shuffle would tell me battery is Low, 50% or 75% - or something like that. FIX IT! End rant.