I think you are right. In my time I didn't find ( or found but not working ) a way to preload Webm files, I think that's the reason.it is because of the galv imgload plugin usage. That plugin can cause issue, if not given time to load and also it somehow depends on the system memory of the player. And if the player is fastforwarding, then again it is known to cause issues.
About updates, I plan to make 2 more.