This could be a problem with the download speed of the stream. I have a similar problem when my girlfriend watch Netflix on TV and volumio plays webradio. Yesterday I was almost insane because the radio suddenly stopped working and I could not find the fault.
Well I have not tested yet, but I found maybe a solution. In the mpd Config file you must increase following lines. audio_buffer_size buffer_before_play
That's just a idea and I want to test it today, too.