I also had some issues with my APM a few weeks after I bought them. Out of the blue, they stopped pairing automatically, I got some random buzzing from the right ear cup (dangerously loud actually!) and some intermittent pops and clicks during songs/videos.
I did a factory reset and they've been flawless ever since.
Retracing my steps, I put the cause down to walking past a running Microwave oven whilst wearing them.
All Bluetooth headphones hate Microwaves as they operate on the same 2.4Ghz frequency, but it seems the APMs are more sensitive to that kind of interference than the other BT headphones I own. There is a lot more going on under the hood with APMs than rival brands in terms of chipsets and active DSP. They can and will get upset by interference.
The main issue here is Bluetooth. As a data transmission method, it's completely dated and useless and I cannot wait for something better to replace it. It operates in an already crowded 2.4Ghz space (Wifi, Microwave ovens, console controllers, Apple TV remotes, Televisions, AV Receivers, neighbour's WiFi and BT devices, the list goes on). It's a lame, weak signal that has always been intolerant of conflicts with other devices. And it cannot even support Apple's soon to be release Lossless audio!
I know it's frustrating but at least we have the ability to reset them. Not even my equally expensive B&O headphones have that ability. This is just the state of play with complex electronics. In an effort to rid us of tedious wires, Bluetooth has made things worse in some respects.
If your WiFi router supports both 2.4 and 5Ghz, switch everything you can over to 5Ghz as it will help with interference.
On a more positive note, the APMs sound quality and seamless integration into the Apple ecosystem more than makes up for any occasional Bluetooth nonsense. Apple always want the best experience for their customers, but their hands are tied by an utterly dated and useless transmission protocol.