Hi
If your title has no background image to go with it on the sequence line (and you want it to be this way) you should add a blank frame to the end of your sequence against which your title will play. I think that should cure the problem. Obviously extend the playing time of this blank to match your title playing time.
I am not sure whether VP is supposed to (or will) play title overlays on their own,(i.e. without a substrate image) the as I have the free version (2.12) which doesn't use them, but in my version at least, sound files will play after the clip sequence line has finished.
Nat