I forgot to mention that the code skip issue was caused by a C++ compiler bug.
I thought to mention it now, because it is interesting as it was a very strange error and the compiler is not even the .NET compiler, but native C++ compiler and so it should be the most reliable compiler of all.
And we have never seen any bugs in it (in about 15years) until now.
Basicly the compiler output wrong native code for a condition check and the code was wrong in a way that the code execution ran into the body of the conditional check even if the condition was false, but then it skipped out executing only the very first line in there.
Now we at least know about this bug in the compiler so we can avoid doing similar condition checks in the future.
And it is still nice though that we found only one bug in 15 years of extensive usage of the C++ compiler.