Shotgun ejectors have spring loaded hammers or rods built into the forearm to activate the ejectors which are triggered as the gun is broken open. Weak ejectors are directly related to weakened springs unless there is a bent part (extractor/ejector slide for instance) binding somewhere. From your question it seems both ejectors are weak in throwing out the empty shells tending to suggest springs weakened through age. Even if one un-cocks the shotgun to relieve pressure on the main hammer springs during storage (preferably using snap caps), the ejector hammers will always remained in the cocked position.

Check the condition of the extractors and what ever springs are used in the forend, possibly broken and if coils will still work in that condition but weaker than undamaged ones.

Of course this diagnoses is contingent on the fire cases not themselves sticking in the chambers caused by rust or pitting etc?