MagicDraw/Cameo: In SysML Activity Diagrams you can only set the allocation mode in to 'usage' or 'definition' for an entire AllocateActivityPartition group at once, not for individual AllocateActivityPartition columns or rows.
This is not a bug as such, it likely corresponds to most users' expectations, but it does mean things can get out of sync when using AllocateActivityPartition (even with validation engine support) unless you are very careful.