When importing MS Projects, the planned start dates are not matching with what imports into the instance.

1. Log in to a demo instance.
2. Navigate to Import MS Project.
3. Import the attached project.
4. Open the project after import and scroll down to the project tasks that are created.

Result: The first project task will have the correct planned start date, the rest will have the same start date as the first project task

 

This is happening because the MPXJ framework (the open source framework used for project import) has an issue with handling certain Microsoft Project 2007 files.

Try saving the file in Microsoft project 2010 and then try importing it again.