There could be many possiblilities...
1) Object not created at the moment of test- Testcompleate can be way faster than the application
2) You have mapped with properties that changes, hence TC searching refers to old properties.
3) Two name mappings created (some how) for same object.
what you can do is create a new project and re-corde same test with new name mapping and bit investigation in to name mapping.
After further inspection I have some more weird behavior to report.
If I use the Object Spy tool it navigates me to a different place in my Object Browser than where the Name Mapping Editor brings me in the Object Browser. I deleted the entire composite in the Name Mapping editor and remapped it from the Object Broswer and it is still bringing me to a different location. When I do "Highlight on Screen" with the orignal object it can find it, but this randomly created object that it's giving me in a different place cannot be mapped.
Is my only solution to delete all my mapping in this shell? I have several tests this will break if I do this.
Perhaps this will help: http://screencast.com/t/JMw3nv5D
