When does the reg2bus and bus2reg are called in UVM register test?

In reply to Vinay Jain:

Hi Vinay,

Thanks for the reply.
Actually, I set provide_responses = 0 in the constructor of the adapter.
I’m also wondering why bus2reg is called twice.

I think the bus2reg is called twice because of uvm_reg_predictor.svh and uvm_reg_map.svh.
I saw it from this link:
https://verificationacademy.com/forums/uvm/uvmregadapter-bus2reg-called-twice-predictor

However, I still don’t understand why it is happening. The second bus2reg is causing an error to me.