I do not think that this is X Plane 11 related. But to make clear, I am on X Plane 11.
The LNAV gets confused at a waypoint that is further down the list once more. In EDDM, there is an approach via MIQ, and MIQ is also on the missed approach path. After passing MIQ the aircraft turns 180°, back to MIQ. The LEGS page is still okay, with the correct next waypoint on top. You have to take over with HDG and copy and paste the top waypoint again to the top then select LNAV to recover, or fly the rest of the approach without LNAV.
Paul