Sounds like the divot is too far out- can you tighten it in more? Or maybe the drill jig wasn't seated against the edge when you drilled?
The XL Connector system only uses 14mm mortises; the drill jig is for the 500 system. That said, the principle is the same.
Was the fence height for the face plunges set to 40 mm? This can trip people up because the end grain plunge is 50 mm deep, but the face plunge is 40 mm from the edge. If you set the fence to 50 mm, it would put the grub screws at the outside edge of the divot and would tend to push the piece apart instead of pull it together.
If the fence was in the 45mm range, it might not move anything at all when you screwed in the grub screws.
