Hi,I merged this bug with the one Vincent mentioned. mdz didn't fix the bug in 0.5.17, but in 0.5.31, so it's normal that it is still present in 0.5.28.6. Therefore Michael's fix was unnecessary. What Michael did is to "break" the example just above the one these two bugs concerned (since they do look alike).
I'm leaving these bugs open until Michael's patch is reverted.