I have a CentOS VM instance which was software encrypted during install. The system booted fine (after entering the boot decryption password).
My project requires enabling FIPS for OpenSSL, so I went through the steps and rebooted.
Now the system will not accept my boot decryption password (which is purposely easy to type).
On an otherwise identical system without software encryption, enabling FIPS using the steps above works fine, no problems rebooting.
Edit
I spun up a third CentOS VM instance, this time not using whole system encryption. Next, I encrypted a volume using luks, then rebooted. I'm prompted for the password and the system then boots normally.
Next, I enabled fips for openssl, rebooted - and get a plethora of errors where I'd usually see the boot password, and the system does not boot.
I booted this system into single user mode, pulled fips=1 from the kernel line and booted. The boot password was accepted this time.