Throwing myself to the wolves, so flame away.
My guess is that with both of the failures shown, hydraulic pressure caused by pin insertion was the main culprit. If the adhesive doesn't have anywhere to go when the pin is put in, then the pressure either cracks the forearm immediately or it remains indefinitely.
As far as fixing. If there aren't any pieces missing...
1. I'd remove the pin.
2. Chuck it up so I can work with it.
3. Blow it off with dry air.
4. Apply Titebond translucent
5. Since the break at the collar looks clean I would apply very slight pressure on the front to keep it in place.
6. Squeeze out excess glue and clean
7. Clamp with surgical tubing
8. Get berated for suggesting ^^^^^