Can you please check if you are using the most recent version of PDF-XChange Viewer (2.5.322.7).https://www.tracker-software.com/produc ... nge-viewer
You also have to know that there is no further development for the Viewer.
It has become discontinued and replaced by PDF-XChange Editor (6.0.322.7).https://www.tracker-software.com/produc ... nge-editor
Even though, when executing a test with superscripted text, I am not able to reproduce the problem. Not via the Viewer, nor via the Editor.
Can you please post an example PDF ?