This is something that we have recently addressed in the code of ArchiCAD. Sorry to hear that it affects your projects as well. A final solution will be available with the next ArchiCAD 16 hotfix to be released this Summer.
The followings might help to workaround the problem:
- rebuild the section elevation
- unload the library that has the marker, rebuild, reload the library
Marton
Marton Kiss
Chief Product Officer
GRAPHISOFT