I used the SD card copier program in the accessories menu. The SD cards are exactly the same brand and size. There were no errors during the backup process. When trying to boot from the backup SD it hangs with the message "dphys-swapfile.service" at the bottom of the screen.
I think I just had too many other processes running during the first attempt. I got it to work by running it again after rebooting and making sure very little else was running while it was copying.