This is not a hardware issue or a bug.
The reason that it is taking so long is that it is doing a secure wipe of the entire hard disk by filling it with random data. The reason that this is being done, from a security standpoint is that it prevents attackers from being able to determine which parts of the disk actually contain your encrypted data, and which contain nothing (because well-encrypted data should be indistinguishable from random data). Unfortunately, security isn't always convenient and this takes an extremely long time (it can take more than 24 hours on larger disks).
However, if you don't care about wiping the disk, then you can select the (poorly labeled) "cancel" button, which will not cancel the installation, but will just cancel the wiping step, and continue on setting up your encrypted volume, albeit possibly at the expense of security.