“Elemental Dawn” reads “This node does not work if Elemental Nova has a cooldown.” It also casts on Arrival. If this was working correctly, with 1 charge and no Elemental Dusk, it should then cast on Arrival - but it does not.
Also, the skill “has a cooldown” regardless of being off cooldown due to an extra charge (potentially) - so the node should not work at all. It doesn’t say “if it is on cooldown”. It states that if the skill has a cooldown at all, the node does not work - and I agree, that it is almost there.
I still cannot find a mechanical reason why it should cast at any point. The skill has a cooldown. Again, were this working as intended, it should cast on Arrival if it has an extra charge, and no node selected to cast it on departure, but it doesn’t. It only casts on departure, and only if you have 1 charge. If this was working correctly, adding a second charge would, by your logic, add a second cast (either on arrival, middle, departure, whichever one it selects first with its two charges) however, it does not.
If this is working as intended, wording at the very least needs to be adjusted, and the mechanics that allow it to work need to be streamlined.