I pretty much agree with Miriam.  My home county time-stamps and indicates reason for correction within the index entry.  Whenever we find an indexing error, we always notify clerk. 

Now, if there is an error on the document, that is another story and has nothing to do with searching the index. 

But if the index entry is not matching the document; or if wrong images are attached to the entry, we notify the clerk.  They are always very grateful and notify us when the correction has been made.