https://ibb.co/s9KWZyKQ
https://ibb.co/VYWnFgCf

Belt build like in the first screenshot get broken upen reverse.

I'll look into it, but I recommend using one of these other alternatives instead:

• Belt Reverser 2
• Belt Reverser Fixed
• Belt Reverser 2.0

While I do try to patch the issues with the version of belt reverser that is included within this mod, I've personally just been using Belt Reverser 2.0 for my own save files

i tested some of the alternatives and they all seem to have the same "issue", after further investigation, it seems this isnt even the mods fault because in this screen (https://ibb.co/YF2wF87v) the bottom belt is the same as top without the splitter, if the belt is reversed, they obviously merge together, however i think this situation can cause unintended/unwanted merging of lines, especially when reversing longer/older transport lines, if the reverser is used frequently.
if this situation is detectable, i suggest, to inform the user with a warning, like when ghosts are still in the line and cant be reversed, and only reverse the belt if the user promts again (or double press)

ps. This Figure (https://ibb.co/CK2xJ1hm) also get permanently destroyed after 2. reverses. I just have the feeling that splitter with perpendicular belt is kind of jacky to reverse with factorio belt logic.

Hmm.. that makes a lot of sense... but if the other mods haven't caught and fixed the issue, I'm not sure how much help I can be.

With regards to the Belt Reverser functionality, the best I can do is reverse-engineer the solutions that the others have already implemented, since I didn't develop the belt code myself, and I don't have a good grasp of how it works (just enough to patch the holes, as I mentioned)

It's also possible that this issue may not have a simple solution? I can't say that I've ever used that particular configuration for longer belt lines, but I can understand that different people work in different ways. I'll try looking into it when I can, but I can't guarantee a solution.

If possible, I would try to get the Belt Reverser 2.0 dev on this; even though that's their only mod and they haven't updated it in over a year (I would argue that's because there hasn't been any issues in over a year). They seemed to have the best handling of the belt reverser code.