In the article "how (un) ethical are you" by banji, bazerman and clugh the authors discuss four related sources of unintentional unethical decision making. one of those sources was a tendency to overclaim credit. according to the article the issues with overclaiming credit are;

I believe the answer is: Destabilize alliances, and take a toll on employee commitment
When we overclaim a credit, we would indirectly make other team members that spent their time for the success feel overshadowed and unappreciated.
This kind of thing,will tend to make the employee no longer feel motivated to give the same effort for future projects

What’s the