A-833 OD gets stuck in second while driving

My A-833 OD gets stuck in between second and third every once in a while upon shifting to 3rd. When this occurs, the car is stuck in second until I get to a stop, crawl under and push the linkage back to neutral. Most of the time, once freed up, I can drive away normally until it happens again at some point. Any ideas on cause here? The trans shifts otherwise normally and the clutch feels fine.