Fc with two Nter X domains doesn't render properly

[AndrewCRMartin]

Fc with two Nter X domains doesn't render properly. It shows just one Nter X domains with the Linker hidden underneath it.

X(1)-L(2)-X(3)-H(4:12){2}-CH2(5:13)-CH3(6:14)-L(7)-X(8)|X(9)-L(10)-X(11)-H(12:4){2}-CH2(13:5)-CH3(14:6)-L(15)-X(16)

Note that this can be drawn - and generates the correct AbML - but when you render (or Tidy) it, it doesn't work.