The tefillin parshios that you see were written on two separate pieces of klaf and spliced together.
Ideally the parshios of the tefillin shel yad should be written on one piece of klaf but it is acceptable if they are written on two separate pieces and glued together. Often I see parshios that are spliced together with no glue. They could easily be separated by just sliding them apart. This is not the correct way to splice parshios. By inserting glue into the seam I was able to make make them 100% kosher.
are after being glued together.