FIPS mode can't decrypt existing passphrase-protected ssh keys

Issue

• It seems encrypted ssh private keys can't be decrypted on FIPS systems. Why? What to do about it?

• We generated a passphrase-protected ssh keypair with ssh-keygen and used it successfully
  After we enabled FIPS mode (e.g., by following instructions for RHEL6), our ssh key no longer accepts our passphrase

  [root]# ssh server.example.com
  FIPS mode initialized
  Enter passphrase for key '/root/.ssh/id_rsa':
  Enter passphrase for key '/root/.ssh/id_rsa':
  Enter passphrase for key '/root/.ssh/id_rsa':
  root@server.example.com's password:
  

• SSH keys not working after FIPS mode enabled on server

• How to create ssh keys in a non FIPS compliant systems so that the ssh keys are complaint after the system is upgraded to FIPS compliant mode.