It is possible that the Logic Pro control surface preference file has become corrupt or the permissions have gone bad. This can cause track data to load incorrectly on the surface for some faders. The problem is usually intermittent and only occurs when switching to a different project.
1. Close Logic.
2. Locate the file com.apple.logic.pro.cs (this is the Logic Pro control surface preferences) in ~/Library/Preferences.
3. Backup it up and then delete the file.
4. Relaunch Logic.