Could you please try creating a new catalog for testing purpose and import a few images in there then try and check if tone curves are working properly in that catalog?
Thanks for the suggestion. I created a new catalog and imported some photos and still getting the same results. Tone Curve is very jumpy and laggy. I figured it was an issue with Sierra since it happened directly after I updated to the new software. I posted it on a thread with other photographers and there were others that had the same issue and had just updated to Sierra as well. Hoping its something that can be sorted out.
Greg, I checked with the team and it has been reported as a known issue.
You can add your vote by clicking on this link Lightroom CC 2015.8: Tone curve still broken in | Photoshop Family Customer Community