I observed the same behavior. Two PT icons in the task bar (OS X). This, however, only happened AFTER one song fizzled with the (in different posts already mentioned) "couldn't load ... skipping to next one happened".
"Little lies" skipped with "Oh Diane" as next one playing fine. After clicking once more on "Little lies" that worked well again. However, there are now always two entries in the log...
I am attaching the relevant (hopefully) bit from the event log:
06-08 04:51:02 WARN - Couldn't open file to try extracting cover
06-08 04:51:02 DEBUG - Song doesn't have cover art
06-08 04:51:03 - Connection reset by client
06-08 04:52:11 DEBUG - Post succeeded: false
06-08 04:52:11 WARN - couldn't map tcp
06-08 04:52:11 - UPnP failed... attempting Bonjour...
06-08 04:52:11 WARN - Router mapping failed. The server canNOT receive connections from the Internet
06-08 04:52:53 - Connection reset by client
06-08 04:52:53 DEBUG - xx.11.37.24 - org8e0vf0r7j - Request: /songs/1191.m4a
06-08 04:52:53 DEBUG - fileName: /Volumes/BigBook/Music/Music/Fleetwood Mac/Greatest Hits (European)/11 Little Lies.m4a
06-08 04:52:53 DEBUG - file size: 7991192
06-08 04:52:53 - philip: Streaming song "Little Lies" by "Fleetwood Mac"
06-08 04:52:55 WARN - Couldn't open file to try extracting cover
06-08 04:52:55 DEBUG - Song doesn't have cover art
06-08 04:52:56 DEBUG - xx.11.37.24 - org8e0vf0r7j - Request: /getAlbumCover/Fleetwood%20Mac-Greatest%20Hits%20(European).jpeg
06-08 04:52:57 - Connection reset by client
06-08 04:52:57 DEBUG - xx.11.37.24 - org8e0vf0r7j - Request: /songs/1193.m4a
06-08 04:52:57 DEBUG - fileName: /Volumes/BigBook/Music/Music/Fleetwood Mac/Greatest Hits (European)/12 Oh Diane.m4a
06-08 04:52:57 DEBUG - file size: 6039903
06-08 04:52:57 - philip: Streaming song "Oh Diane" by "Fleetwood Mac"
06-08 04:52:57 WARN - Couldn't open file to try extracting cover
06-08 04:52:57 DEBUG - Song doesn't have cover art
06-08 04:52:57 DEBUG - xx.11.37.24 - org8e0vf0r7j - Request: /getAlbumCover/Fleetwood%20Mac-Greatest%20Hits%20(European).jpeg
06-08 04:53:01 DEBUG - xx.11.37.24 - org8e0vf0r7j - Request: /songs/1193.m4a
06-08 04:53:01 DEBUG - fileName: /Volumes/BigBook/Music/Music/Fleetwood Mac/Greatest Hits (European)/12 Oh Diane.m4a
06-08 04:53:01 DEBUG - file size: 6039903
06-08 04:53:01 - philip: Streaming song "Oh Diane" by "Fleetwood Mac"
06-08 04:53:01 WARN - Couldn't open file to try extracting cover
06-08 04:53:01 DEBUG - Song doesn't have cover art
06-08 04:53:01 - Connection reset by client
06-08 04:53:33 DEBUG - xx.11.37.24 - org8e0vf0r7j - Request: /getAlbumCover/Fleetwood%20Mac-Greatest%20Hits%20(European).jpeg
06-08 04:53:33 DEBUG - xx.11.37.24 - org8e0vf0r7j - Request: /songs/1191.m4a
06-08 04:53:33 DEBUG - fileName: /Volumes/BigBook/Music/Music/Fleetwood Mac/Greatest Hits (European)/11 Little Lies.m4a
06-08 04:53:33 DEBUG - file size: 7991192
06-08 04:53:33 - philip: Streaming song "Little Lies" by "Fleetwood Mac"
06-08 04:53:33 WARN - Couldn't open file to try extracting cover
06-08 04:53:33 DEBUG - Song doesn't have cover art
06-08 04:53:34 - Connection reset by client
06-08 04:53:39 DEBUG - xx.11.37.24 - org8e0vf0r7j - Request: /songs/1191.m4a
06-08 04:53:39 DEBUG - fileName: /Volumes/BigBook/Music/Music/Fleetwood Mac/Greatest Hits (European)/11 Little Lies.m4a
06-08 04:53:39 DEBUG - file size: 7991192
06-08 04:53:39 - philip: Streaming song "Little Lies" by "Fleetwood Mac"
06-08 04:53:39 WARN - Couldn't open file to try extracting cover
06-08 04:53:39 DEBUG - Song doesn't have cover art
06-08 04:53:40 - Connection reset by client
Not sure, whether the warning on router mapping started the issue... see 06-08 04:52:11
Streaming worked actually all the time quite well, except for the short hickup with "Little lies"
Hope this helps in clarifying open issues.
Cheers