There is no such expression as ‘unwinding a discount factor’ !!!!
It is meaningless.
I think you are confusing it with ‘unwinding the discount’. What that refers to is that if you owe money payable in (say) 5 years time, then the present value will mean discounting it for 5 years. However, in a years time, the present value will mean discounting it for only 4 year (which will obviously give a different present value). We call this effect unwinding the discount (not unwinding the discount factor).
There is no way that this would be referred to in Paper F9.