How to reproduce (note: the quotation marks “” are different from "") :

~~~~
$ mkdir test; cd test
$ count=0
$  while [ $count -le 20 ]; do
$ touch "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua “” $count"
$ count=$((count+1))
$ done
$ cd ..
$ genisoimage -udf -o test.img test
~~~~

Result: only the first file appears.