Preliminary data but never published

Case: Dr. M researched and established preliminary data but never published these findings. Subsequently, Dr. M left the home institution to take a position in another area. Her original work, however, remained with the home institution. Other postdocs built on her findings—some of which were in error, due to some technical issues which they resolved—and published her data and their own. She, Dr M, felt that she should have been recognized; even listed as a coauthor.
Question.: What is your opinion and why?

Sample Solution