How to reproduce:
1. Open the attached “IN-108832” project
2. Navigate to Edit → Preferences → External Tools
3. Change the “External Script Editor” field to Rider
4. Press the “Regenerate project files” button
5. Open the Project folder and open the “Assembly-CSharp.csproj” file using Rider
6. Press “CTRL” + “F” to open the search bar
7. In the search bar input “AdditionalFiles Include”
8. Observe the “<AdditionalFiles Include=… line”

Expected result: The “<AdditionalFiles Include=...” line shows the correct relative path to the local package file
Actual result: The “<AdditionalFiles Include=...” line shows an incorrect path pointing to the Packages folder instead of the actual local package location.

Reproducible with: 3.0.31(6000.0.43f1, 6000.1.0a1), 3.0.36(6000.0.54f1, 6000.1.13f1, 6000.2.0b11, 6000.3.0a3)

Reproduced on: Windows 11
Not reproduced on: No other environment tested

Note: The relative path is shown correctly when using Visual Studio 2022