Hey Horia0502,
Sorry about the glitches, the issue does arise with issues in physics interactions. If by any chance you have lower fps, the issue might be worse. I'm also currently trying to optimize the game so users can get better Fps and will solve some of the issues with the wagon. Also, the wagon tearing apart is a result of the horse getting too far away from the wagon. I'm looking into ways to mitigate this issue.
Thank you!