If it were the former, then everything could be called coincidental, and this would just be a problem unique to the Saint Lord of Wind and Thunder, something the Jade Emperor could easily resolve.
Whether through threats and bribes, trying to snatch the Great Law Decree Technique from the Saint Lord of Wind and Thunder's hands, or truly resorting to a murderous move, paying any price to completely suppress the other's Incarnation here, either way, there is a solution.
Keep in mind, within this boundless Chaos Void, even True Immortals can't guarantee that their Incarnations are invincible, and it's commonplace for the Incarnations of True Immortals to fall for various reasons.
Moreover, even if the Incarnation of a True Immortal falls, they would still obtain memories from their Incarnation, knowing how it perished, unable to prevent it without special methods.