I experienced the same issue time ago, but didn't care to report it at that time.
In my current translation, when I export a docx file that was OCRed from (I suppose) a PDF file, on a certain page with a dark blue background the font color is black (it's white on the original document).
Since I can open the exported file myself I can change the color easily, but it would be nice if CTE didn't touch it during conversion.
That's the point of the OCR filer to let the user handle OCRed documents smoothly by reducing the number of tags which result from multiple font or color changes in the OCR processing. Such documents tend to tag the slightest change in the shade of the OCRed image, interpreting it as a color change. If the color is important to you in the OCRed document, please try using the regular filters for the given file type, or just do what you did to the exported file.