Though I'm hesitant to suggest that they'll get the minutia of it correct in implementation, the Loading property limits you to one shot per action/bonus action/reaction only, not one per turn - so it impacts fighters with extra attack, for example, but if you're a fighter who has haste, and a feature that lets you make an attack as a bonus action, you can still us the same crossbow to fire with your action, your haste action, your bonus action, your action surge action, and potentially your reaction, all on the same turn, without 'loading' slowing you down. It's a bit of a silly quirk to the rule.
