Steps to reproduce with default-generated Doxyfile of 1.8.5:

/// class Base
class Base {};

/// class Mixin
template<int ID,class T> class Mixin : public T {};

/// class Derived
class Derived : public Mixin<42,Base> {};

/// class Leaf1
class Leaf1 : public Mixin<43,
Derived> {};

/// class Leaf2
class Leaf2 : public Mixin<44
,Derived> {};



Actual results:

Inheritance diagram for Leaf2 is broken (incomplete). See also diagram for Derived.

Expected results:

Inheritance diagram for Leaf2 should look similar to Leaf1.