You also encounter this issue when attempting to install Ubuntu 20.04 / Mint 20 on a LUKS encrypted volume or LVM on LUKS if you've created this encrypted volume manually before starting the installation and not using the wizard.
You also encounter this issue when attempting to install Ubuntu 20.04 / Mint 20 on a LUKS encrypted volume or LVM on LUKS if you've created this encrypted volume manually before starting the installation and not using the wizard.