From what I can see, it didn't seem like you triggered that cascade of error messages in the console from that log. Did your audio still cut out?
I think I have nailed this problem down. Once a a voice line script finishes printing, it is supposed to 'arm' the next script to play after a certain amount of time has passed. This is done through Unity's coroutine functions, and I suspect the problem is that in some circumstances (e.g. if your computer is under load) the coroutines aren't firing properly. I've modified the manager slightly to record the time the next script should be fired. Then it checks whether or not the current in-game time has gone over this flag before arming the next script, so it should run independently of any coroutine nonsense.