Thanks, guys. Did a visual inspection of the flywheel and the starter - no issues. All teeth are present and in perfect condition on the flywheel - no warping. All teeth on the starter bendex are good, edges are chamfered as expected. No odd wear marks, etc. I'm stumped. Here's a video of it making the sound. If anyone has an idea please let me know. Thanks!
https://youtu.be/VRf6RJPdt6o