[web2py] LOB variable no longer valid after subsequent fetch - again

[JC11]

Hello,
I am migrating a web2py app. to Oracle.  It works fine on postgresql
and sqlite, but my firm demands Oracle.  There is a large field in my
db ( > 4000 chars) so can not be a string.  Oracle creates this a
clob.  Often (but not always) I get the dreaded error: 'LOB variable
no longer valid after subsequent fetch'.

I have dug around and uncommented a 'FIX' in gluon/sql.py:
elif fieldtype == 'text':
        if dbname == 'oracle':
            return ":CLOB('%s')" % obj.replace("'","?") ### FIX THIS
I also tried :
            return ":CLOB('%s')" % obj.replace('\'','\'\'')
both let to even more errors.

Is there a fix for this ?  (Python 2.6.5 on Linux, web2py Version
1.76.5)

Thanks,

John C.