Once text has been recognized by the OCR process, it is placed on an invisible layer above the image of text that you can see. When you copy text, the text is copied from this invisible OCR text layer.
Text from the OCR text layer is a close, but not perfect, rendering of the bitmapped text. You will need to proofread and edit the text that results from OCR. When you copy and paste the OCR text, you may notice some inaccuracies which you can correct at that time.
View the OCR Text Layer:
To completely remove the OCR layer from a document:
At this point, you may redo OCR, or use the document as is. If you want to remove the OCR from a document to redo it, you may Force OCR.
(Advanced feature of Kofax Power PDF for Mac). See Editing the OCR Layer.