It could be many reasons. Most common reason lately has been the stop sales order to wait for a chip install -- radio, 360 camera, cruise control, etc. have been common for recent orders.
Mine was built Jan 26 and is showing 'Produced, not shipped.' Hoping it will be here by the end of the month, but not likely.
You can check
https://bmw-recall-tool.netlify.app/ to see if there are any open recalls. Just enter your VIN.