Domino loose tenons let go on a built-in, now I'm back to dados

I've been using the Festool Domino for years on cabinet carcasses, figured it was solid. Last month I was assembling a wall unit for a client near Portland and two of the tenons just sheared off when I clamped the case square. Glue failure or maybe my mortises were too deep, but it happened twice in one afternoon on the same joint layout. I ended up having to cut the whole job apart and start over with plywood dados and screws. That rebuild cost me an extra 6 hours and about $80 in new ply because the original panels were toast. I still own the Domino, but now it only gets used for face frames and trim, never structural boxes again. Has anyone else had loose tenon failures on cabinets that carry real weight, or am I just using too much clamping pressure?