Stopped (with error) /dev/dm-1

I am using full disk encryption and an encrypted swap partition. On every shutdown I get the following Error:

Okt 20 09:03:52 kronos systemd[1]: Deactivated swap /dev/dm-1.
Okt 20 09:03:52 kronos systemd[1]: Stopped (with error) /dev/dm-1.
Okt 20 09:03:54 kronos systemd[1]: Stopped /sys/devices/virtual/block/dm-1.

# /etc/crypttab
swap           /dev/sda3                         /dev/urandom            swap,discard

# /etc/crypttab.initramfs
cryptroot   /dev/sda2   none    discard

$ uname -a
Linux kronos 4.2.3-1-ARCH #1 SMP PREEMPT Sat Oct 3 18:52:50 CEST 2015 x86_64 GNU/Linux

$ systemctl --version
systemd 227
+PAM -AUDIT -SELINUX -IMA -APPARMOR +SMACK -SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD +IDN

$ lsblk
NAME                                          MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINT
sda                                             8:0    0 335,4G  0 disk  
├─sda1                                          8:1    0   500M  0 part  /boot
├─sda2                                          8:2    0 319,9G  0 part  
│ └─cryptroot                                 254:0    0 319,9G  0 crypt /
└─sda3                                          8:3    0    15G  0 part  
  └─swap                                      254:1    0    15G  0 crypt [SWAP]

Start with the shutdown journal lines for /dev/dm-1 and compare them with the supplied /etc/crypttab and /etc/crypttab.initramfs entries. Reproduce the shutdown with the encrypted swap configuration and inspect the generated systemd device and swap units. Done means identifying the cause of the stopped-with-error status and documenting or fixing the behavior with a reproducible test.