[support] Apache solr outputting (, , , ) at the end of snippet

[Christopher M. Jones]

I notice that at the end of the snippet returned by Apachesolr search, 
some nodes get (, , , , ) at the end. The number of commas seems 
variable (?).

On another site where I use solr, I got (tag,tag,tag,tag), where tag was 
the same taxonomy term repeated many times.

So, it seems that the empty (, , , ) is taxonomy related-- based on my 
experience on the second site.

I am using the "categories" module on the first site (the one with the 
empties). That may be relevant, since that module (an older version) 
plays funny games with taxonomy.

My question is:

1. Where are these empties coming from?
2. How do I remove them? I don't need taxonomy info in the snippet, 
though I do want that data indexed and the node biased by it.
   a. Where does the snippet get generated?
   b. Is it hook_able?

And if anybody wants to tell me why, on the second site, I got the term 
repeated about ten times, that would be a bonus. The only thing that got 
rid of it was deleting the node and creating a new one. Tried 
reindexing, tried deleting the index and reindexing.