Well yes, actually I do.
This happens when you rename a dtsx file outside of the project (ie, in the file system) and then load the package in a project. The project will not complain because it has the right file name but … the package itself knows it’s not the same. So open the package and press F7 or right-click the package in the solution explorer and click ‘view code’.
If you scan down a few lines, you wil see
DTS:ObjectName=”old_package_name_without_extension”
Change the value to reflect the new name (without the .dtsx extension) and you’re all set.