Please, open only one thread per question - you'll get answers when I (or someone else) has the time for it :)
Could have different reasons, e.g. if the player controls are blocked, that could prevent other events from starting. This can be fixed by enabling In Blocked Control in the event interaction.
Or, if both events have Blocking Event enabled in their Event Settings node - the event in the next scene starting when the scene is loaded would be blocked by the event loading the scene.