Hunter Kerbin

I think that this may be the reason for many failed constructions currently, as mirrored symmetry is being used much more often due to the revised symmetry selection tool cycling through mirrored to get to other placements. if you place 2-way symmetry parts then use mirrored symmetry to place parts upon these, while the primary part is placed correctly, the mirrored version of the part is unconnected to the rest of the assembly and will cause structural failure