I think it is some thing to do with the fuel management system, the car applies the equivalent of choke for a minute or so after start up, then the system settles back to into its normal setting.( Some thing to do with a ‘closed loop setting )
In mine you can see the rev counter bobbing and the power is uneven for the first mile or so. Best to just take it easy and let the thing warm up properly and there will be no problems.
I think it’s a conman thing on many modem high performance fuel injected engines.