https://www.reuters.com/legal/elon-musk-sues-openai-ceo-sam-altman-breach-contract-2024-03-01/
Could this due to Elon starting up his own A.I company Grok last year?
Most likely reason is because he is just bitter because he couldn't do his hostile take over with OpenAI.
There's no breach of contract as there is no contract or agreement to be breached. So this seem to be as desperate as his earlier richest man alive sues non profit organization.
I don't know why he makes these, but it seems to be some sort of virtue signaling as he wants to be a savior and accepts no one else saving the world, so he thinks these would make him seem good or cool. Or maybe he just doesn't understand law well enough to see these are pointless. And his lawyers won't advice otherwise as they get paid anyway.
Here's open AI's response with emails from musk included - https://openai.com/blog/openai-elon-musk