Mp8008, mp8009 Transformer

The data sheet states that the secondary winding - 24 volts, while the auxiliary produces 12 volts.

also Is there a reason why d2 is 9.1v?
I designed d2 as 12v, and the auxiliary winding outputs 12v.
By the way, do you know why burnd d2 when connect d11?

I look forward to your prompt reply.