Many thanks for the gdb output. Whilst I haven't been able to mock up a way of reproducing this yet it does look like the buffer is blown when scanning for the end enclosing character once one is found.

The user is outputting data using:

mysql --defaults-extra-file=<.cnf file> -h <server> --compress --quick --skip-column-names --default-character-set=utf8 -Ns -D $schema --execute="select * from $table" > $table.txt

Then importing with:

cpimport -E '\"' -e 1 -n1 -s '\t' $schema $table $file

The user has been told to use -B on the export instead.

My guess is we need to create a table that will spit out at least 1MB of data once a quote is in the output so that there is enough data to blow the buffer.