fwiw, tracing, the problem appears to be this line ---- ((eq (string-to-char cell) ?\") (read cell)) ---- in =org-babel-read=.
presumably there are many cases where this is the right thing to do. but, maybe look for a simple =^"[^"]*"$= (i.e., a quotation mark, some other stuff, a quotation mark, and *nothing* else in the cell)? or (heaven help us), something more complicated, with random escaped quotation marks inside the "cell"? cheers, Greg