I have generated the flattened PDF. In that PDF the superscript is not visible.
Instead of the superscript text some blank space or square are appearing.
For example : Square Metres (m²)
In this above example (m) is visible in PDF, but the (2 – superscript) is not appearing.
We provided a reply to this request on this thread last Friday morning. It appears the PDF font is causing the issue. Try changing the font and let us know the results of your efforts.