And with w6 i had a problem with playing played!... I never used it before but a week ago i did and the music only played for + 50% and than the next song started to play.... Also one time this happend...
With 0.9w-6 this certainly happened. Solved in 0.9w-7.
About the other thing, let me know when you have it again, with or without sequence that you know of.
I know you can create "anomalies" by clicking on another track while playing. You can see it : let a track run for a minute or so, and then just click on another track which is much longer or shorter. The time scale changes because of that, and is not related to the currently running track anymore. Some "feature" which was introduced in one of the later versions. Is in there to explicitly solve some other problem, and conflicts with just clicking a track.