Most types of block devices can be encrypted using LUKS. From anaconda you can encrypt partitions, LVM physical volumes, LVM logical volumes, and software RAID arrays.
Source: Fedora Disk Encryption User Guide
If that doesn’t work for you for some reason it is most likely a bug.
So basically if you select “Encrypt” right next to Device Type Anaconda infers that you want to create the LVM first then LUKS. Which means it will encrypt this logical volume ONLY and not the whole drive.
To get the behavior that I want I have create a new Volume Group by clicking the dropdown from “Volume Group” and then selecting “Create a new Volume group” and then on that dialog check Encrypt.
Pro tip: If you want to leave some space of snapshots then on the Volume Creation dialog select “Size Policy” as “Large as possible” and then on the “Desired Capacity” on the main screen input a size than that of the total Volume Group. This leaves some free space for other logical Volumes like snapshots.