Reply To: Unwanted character style added to index

I have a related problem. I have created an ‘Invisible’ Character Style in order to get cross references with short form Fig. (See https://forums.adobe.com/thread/2428581#).
However having created an Index for some reason each line in the index now concludes with the ‘Invisible’ Character style, including just before page numbers and cross refs. As a result the display of the index is incorrect. I can fix up by doing a character style format replacement back to ‘None’. But why is this happening? Not sure why the index is picking up the ‘Invisible’ Character style?