Solved: Seamless branching gone wrong. Can someone asist?

[LogicDeLuxe]

Edit: problem solved and link updated.

I'm trying to create a multi-angle and seamless branching demo DVD with a tool I'm coding. So far, it works most of the time, except I got one scene which totally fails on my standalone SEG player. (which is very picky about correct buffering.)
On it, all runs perfectly seamless, except for VOB id 5, Cell 2. There, the video gets very jerky and also plays one chunk from VOB id 4 inbetween which it is not supposed to. This problem does not occur on any of my software players and neither on the PS3.

There must be some detail I did not think of yet, or some unnoticed bug. Can someone please check my test image? Maybe you can find an oversight.

Note, that there are no seamless angle pointers yet, which is on my todo list. However, since neither VOB id 4 nor 5 are part of any multi-angle scene, that can't be the problem.

Get the image (7 MB) here: http://www.abmischung.de/branchtest.7z