What type of wood is being glued? I ask because I had a similar situation of joints separating when I "upgraded" a SIG kit's wood to a much harder wood. I replaced soft balsa sticks with non-balsa sticks that were much harder. Iused Titebond IIat the time.

You have brought up a question as to the efficiency of a glue across hardness and types of wood. When I tested Titebond & Elmer's in this thread the wood I used was medium balsa (SIG aileron material) . Perhaps Elmer's exceeds the capability of Titebond with medium balsa wood but another glue is more effective as a standard across balsa soft, medium, hard, hardwood, lite ply and standard ply.