Exporting to PDF changes the scale size.

I am trying to create a printable map at 1:8000 scale. On the layout screen, the proportional scale and the scale bar are correct and match each other. When I export the map to a pdf, the scale is off. See attachments, both were set to 100%. I have already doubled checked that the "Clip Output to Graphics Extent" is unchecked. Since I have not actually printed the map yet, I know that it is not a print option (fit to paper vs fit or shrink).

Any help would be wonderful.

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