Just spent the last couple hours creating a dialogue system and I can replicate your problem. I think we need to do another pass on the audio - I can get the first line of dialogue to show as text and play a sound but although the second line of text shows the audio isn’t playing.
Gonna keep at it 
Going to have to come back to this. My setup is a little different to yours, but I can’t get the second sound cue to play either. I have a feeling that this is because we’re not moving through the Data Table rows properly. Although my text dialogue moves on, the Line ID keeps dropping back to 1 - it never actually gets to 2 when I interact with the NPC to get the next line of dialogue. The dialogue comes up as text, but not as audio…
I think that whatever is driving the text dialogue along isn’t interacting with the sound cue in the same way - but I can’t figure it out…
I’ll take another look tomorrow. It is pretty stubborn!