On Journal Entry, Rate value is different from the other item line

Hi all,

my customer is making a journal entry when this happen. Please refer to the Rate column and the cell value in red rectangle. The value of the rates on this column are prefill accordingly. But the value for the last item line is different from the previous line.

I am trying to find out the cause of this problem but after checking, I still clueless how this happened.

Anyone can help me?