Since ubiquity does not run ecryptfs-setup-swap as chroot, there is also another problem: unencrypted swapfile entry in /etc/fstab is not commented out as it should, so you get
/swapfile none swap sw 0 0 /dev/mapper/cryptswap1 none swap sw 0 0
instead of
#/swapfile none swap sw 0 0 /dev/mapper/cryptswap1 none swap sw 0 0
Since ubiquity does not run ecryptfs-setup-swap as chroot, there is also another problem: unencrypted swapfile entry in /etc/fstab is not commented out as it should, so you get
/swapfile none swap sw 0 0 cryptswap1 none swap sw 0 0
/dev/mapper/
instead of
#/swapfile none swap sw 0 0 cryptswap1 none swap sw 0 0
/dev/mapper/