Audio Stopping when layer launches

Hi

I have a slide with audio on the base layer - it starts playing when the slide starts but i also need another layer to appear as soon as the slide starts.

Within a second of that layer starting, the audio on the base layer stops.

The layer properties shouldn't be causing this:

but I cant figure out what to do to keep the audio playing in the background.  I have tried re-adding the audio and changing the trigger for the launch of the layer but still the audio stops after a second.

Ideas?

Thanks

Graham