This is most likely because you tried to rename the program outside of RoboDK.
This is a limitation we have with Fanuc and some other robot manufacturers. As the program name is "baked" in the code, you can not manually change the program name after you generate it, or if you do, you need to manually modify it in the code also.
The best way is to modify it in RoboDK before generating the LS file.
Jeremy
Find useful information about RoboDK and its features by visiting our Online Documentation and by watching tutorials on our Youtube Channel.