One of our users attempted to shadow the bib record with ID 168475. This record has a LOT of items and holdings associated with it. They got a stacktrace in their browser that didn't shed any light on the problem. When I looked in catalina.out, I found that the first exception resulting from saving the record was that the row OLE tried to create in the bib_audit_t table had a value for the COLUMN_VALUE column that was too long. That column was already a blob, which apparently has a max length in MySQL of 65535 characters. I modified the column to be a longblob, and that seemed to fix the problem for now. It's pretty unlikely we'll hit the character limit for a longblob, but who knows.
So we have a fix, but I wanted it on record that we made this change to our database, and I want to make sure Giri and Suresh don't anticipate it causing a problem. Also it would be better if OLE handled the problem of failing to insert an audit row more gracefully than showing the user a stacktrace and failing the whole transaction.