Sometimes when I am listening to music a song will end and then I hear silence. I check the screen and a new song is playing but I hear no sound. If I pause it and press play again I am greeted to a horrific hissing sound that doesn’t stop even when I pause again forcing me to unplug the headphones. If I remove the headphone jack and play on the speaker it plays fine. If I stick the headphone jack back in when it is playing through the speaker it transitions back to the headphones fine. If I plug the headphones back in when it is paused and press play again the hissing starts once more forcing me to unplug again. Very strange software issue. At least there is a workaround other than restarting the phone. Anybody else experience something like this? Perhaps I have done a poor job explaining this.
I have experienced exactly the same (save for your suggested workaround which I will try at the next opportunity) and I think it’s a symptom of the ongoing audio issue discussed here:
As I was typing the original post I tried that out and it worked. For months now I have had to restart. Great to find a workaround. I hope it works for you if the problem does happen again. Please post here if it does. Could help some people out
Hi Dean, what you described is clear.
I experience a quite similar issue. In my case it does not happen while I am listening to music but when I start listening to and it does not concern hissing but silence.
Let’s say I use the headphones five times in a day (between a shut down and a power on of the FP3). Everything works fine until I insert the jack socket until the fifth or the sixth time in a day. Over that amount of times - more or less - when I insert the jack socket and I press play, the music player starts but I hear nothing. When the latter thing happens if I disconnect the jack and press play, I do hear the song through the external speaker. But if I then try to insert the jack again (no matter in my case if the song is playing through the speaker or not in the meanwhile) I hear nothing again.
I did not yet find any other workaround apart from restarting the phone. Once the FP3 does a restart, everything works fine again.
Very strange. I have hissing which is so loud it hurts my ears. Sometimes play then insert headphones doesn’t work for me either sometimes. I play, pause, play, pause, play then insert 
That seems to work. Maybe it is giving the phone time to restart whatever driver runs the headphone jack?
Had the same problem today. In fact after a while the phone ignores the headphones and plays the sound through the speaker, restarts solves the problem but what is causing it in the first place? If you disconnect and reconnect headphones you get the hissing sound through the headphones.
I’m currently communicating with support and this is how I have described the issue:
There’s no sound from speakers, no sound from headphones.
Upon headphone jack insertion there is no short high pitched (beep) sound you hear when you insert the jack when there IS sound.
Volume control working as it should but no sound coming out.
All apps behave in the same way, i.e. music playing no sound, video playing no sound, youtube playing no sound.
step 1: Volume control working as it should, all at max volume, but no sound coming out.
step 2: headphone port is clean
step 3: earphone FAIL no sound, speaker PASS Asian woman singing, but still no sound from speaker using apps.
Also no sound from earpiece when calling, only from the loudspeaker.