Hi
Works OK in 10.56 Before and after saving project are identical and Levels effect settings are as they were when the project was saved. No sign of a reset.
If you say that the effect settings have returned to normal when you reload the vpj file you saved then that is odd. They should still be set as they were when you saved. They should not reset themselves. Check that you are not re-loading your project from an exported project.
If you saved the project by exporting it, the reloaded clip will (of course) show the Levels effect you made but if you then open the effect it will show the graph reflecting the changed RGB since it is essentially a new image. The Level settings will be back to normal as they would with any new image.
Are you reloading the project from a saved vpj file or a saved (exported) project? (Just a thought)
Nat