Here is an experiment to demonstrate a problem.
The sound on a pi vs sound on a desktop pc.
When I run the command numerous times on the pi, the sound stop and will not continue…
gst-launch-1.0 filesrc location="./Music/04 November Rain.mp3" ! decodebin ! audioconvert ! volume volume=4.0 ! pulsesink
If I wait a few mins. the command will begin to work but quit play the sound again after a few repetitions.
This is not the case on my desktop ubuntu machine.
The implications of this are when you are giving commands to your raspberry pi, the pi will suddenly go death and not respond again until you reset the raspberry pi.
Is the source of the problem the pulseaudio with the raspberry pi sound module, I am not sure.
I am going to retire my raspberry pi 3 mycroft project as something that is not ready for my needs.
Strangely I have mopidy running on my raspberry pi 2 with no troubles at all. It simply is not using mycroft.