Shared lib is not loaded although rpath is set properly

[JoeCFD]

There are two shared libs in the lib path which is set with rpath in cmake. One is OK and another one is missing when I check my app with
ldd myapp

What could be the cause?

One possible reason is that this lib uses other libs which have to be set with rpath as well.
When I check all libs it links to, they are all in the system lib path.

If the path is set with LD_LIBRARY_PATH, myapp runs fine.

[JoeCFD]

Two versions of this lib are in the machine. Therefore, there are conflicts. Removing one solves the problem.