Comment 27 for bug 269082

In case sdl checks for a local device this indeed would explain the probem ... LTSP starts a pulse daemon on the client and usually has the esd as well as the native pulse plugins installed server side.
On login PULSE_SERVER as well as ESPEAKER (pointing to the client) get set in the session on the server and asoundrc creates a virtual pulseaudio device, so all sound output gets forwarded to the pulse daemon running on the client, be it esd, alsa or pulse sound.
If the app tries to attach to the local device on the server but is told to actually forward all sound traffic on a higher level via the network there is indeed a discrepancy, since the found sound device is definately not the actual output device no matter which of the drivers you use.