For viewing files in LDView, the Seam Width setting in the Geometry tab of preferences is what is causing this. Uncheck the box to disable seams. For POV exports, the Seam Width setting in the POV Export Options is what is causing it. Set the value to 0 to disable seams.
Note also that if you look at the POV file in a text editor, there will be a LDXSW value declared near the top of the POV file (set to whatever the setting was set to during export). Changing that value to 0 in an existing file will get rid of the seams (in case you had just the perfect camera angle, and don't want to have to reproduce it).
Note also that if you look at the POV file in a text editor, there will be a LDXSW value declared near the top of the POV file (set to whatever the setting was set to during export). Changing that value to 0 in an existing file will get rid of the seams (in case you had just the perfect camera angle, and don't want to have to reproduce it).