Might be a bug or it could my expectations (again). However the problem could be at the root of people having difficulties placing pivots.
If you rotate a parent them translate its child using LOCAL axes the child moves and positions as you would expect.
However if you rotate a parent then translate its child using WORLD or use position the child moves again in the direction of LOCAL axes but distances depend on the rotation of the parent.
The PG http://www.babylonjs-playground.com/#1J7LGZ shows the effect. The cylinders mark the positions of the child mesh (the pilot) as it and the parent (sphere) move. The red cylinder marks the expected final position following the final move of -2 in the direction of the world x axis. The pilot meshes show the actual positions.
Commenting out the pilot and sphere moves and uncommenting them in turn will show the sequence.