The website is not using ezfind.
It runs on a small dedicated server. I think ezfind is a bit out of this customers ballpark.
The website runs stock eZpublish 4.2
I have enabled binary search indexing
of pdf content object files. But no kernel related modifications.
I found deleting the contents of ezsearch tables
and reindexing the site fixed the problem in the short term. Still it would be much better if this negative feature was better documented.