Sounds like a bug but I can't seem to get it to happen myself. Can you email me a sample of text where you're seeing this problem? If you can, please send to me at firstname.lastname@example.org
If you're just trying to prevent the symbol from being sent to the voice engines, you could also try setting up a character filter until we figure out what is going on with search/replace. From the TextAloud menu, click Tools -> Text Processing -> Character Speaking and Filtering. Click the Add button, and on the add dialog, use the option 'Filter Character', and place some characters to filter, including the ¬ character, in the field labeld "Characters:"