Please don't simply re-open bugs without consulting with the maintainer.
In your case, my understanding of cryptsetup is that it creates a devmapper device exposing the *unencrypted* data on the partition. It is quite correct that udev ignores /dev/sda4 - it is an encrypted swap, and udev can do nothing with it.
Instead you should use the UUID of the actual unencrypted devmapper device. What does ls -l /dev/mapper show for you?
Please don't simply re-open bugs without consulting with the maintainer.
In your case, my understanding of cryptsetup is that it creates a devmapper device exposing the *unencrypted* data on the partition. It is quite correct that udev ignores /dev/sda4 - it is an encrypted swap, and udev can do nothing with it.
Instead you should use the UUID of the actual unencrypted devmapper device. What does ls -l /dev/mapper show for you?