To Reproduce:

1. Create a project and set up p4.

2. Add a Terrain or any other asset to project view.

3. Submit it.

4. Close Unity and open the project with a newer version of Unity (tried 4.3.3 to 4.3.4 ,4.5.3p3 to p4 and b3 to b4).

5. Don't check out the asset, reserialize the file ( did this by toggling between force text and force binary).

6. Open the file through a text editor, notice it has been edited ( for example the version was changed as in the attached screenshot) but that is not reflected in p4v.