Thank you for submitting your idea to help us improve SDL TMS. In the current editor, the fuzzy match percentage is reset to zero as soon as the segment is edited and that is why you see the zero there. SDL Trados Studio, however, maintains a reference to the original fuzzy match percentage and displays this. We can't change the way that we show the percentage match in the review interface as this would be a change in behaviour and we never know who may be relying on current functionality. However, we are open to looking at other ways to display this information so I'm going to put this under community review for now.
As a workaround, you can click on the clock icon to the left of the segment which will show the history of the segment. This will show the translated text at each step of the workflow and checking the text as it came out of pre-processing will show whether there was a fuzzy match. You can also then see the changes that were made during the translation step.