Hi lionn77,
you are right. There is a bug in the scr layer. Bigboywooly (GWX campaign master) and I discussed this in the past (more than a year ago. There's a thread somewhere at Subsim). More recent versions, e.g., the W'haven Schleuse Mod, don't have this problem.
Cheers, LGN1
Edit: You can find a discussion about this issue here:
http://www.subsim.com/radioroom/show...61308&langid=1