I experience the very same problem, and it's very annoying because I have a lot of fresh tracks with voice markets in it, but I'm only able to hear the very first marker in the track.
I'd be happy to assist, by providing more details, testing, etc..
As voice records is main feature, which makes mappers choose Columbus tracker, I believe, we can rise priority of this issue till major. Personally for me it's blocker.
Unfortunaltely I've never done Java programming, nor I've looked in code of JOSM, to help with more.
