Did they had an urgent need for cash?
My thoughts for real and that be, after reading the part of the referred document in OP which states as follows;
The news outlet reportedly viewed documents on the firm’s financials showing roughly $5.2 billion in total expenses for 2022, and $5.4 billion in 2021 and 2022 for acquiring property and equipment in addition to research and development costs.
That's just a snippet from the original and you could with that colluded that Musk group after spending about $10.6billiom in expenses, they've got go reciter some or get some profits from all there investing.
The issue with them having to sell now is that they sold when the market isn't in its full bloom as we hope this to happen next year but, you never can tell, it could be a dump to bug back strategy, Musk is good for it so, the game is on those that would follow and sell instead of increasing there portfolio.