cannot install ubuntu on luks btrfs uefi multiboot sda3

[VS]

tried to follow this
https://teejeetech.in/2020/09/05/linux-multi-boot-with-refind/
https://teejeetech.medium.com/linux-multiboot-with-btrfs-luks-and-efi-part-2-7b0896c03cce

set sda3 as efi partition for boot and boom got this bug. My root is btrfs. I already have refind and manjaro installed on existing luks btrfs root filesystem as per the links i followed.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubiquity 18.04.14.15 [modified: lib/partman/automatically_partition/question]
ProcVersionSignature: Ubuntu 5.4.0-42.46~18.04.1-generic 5.4.44
Uname: Linux 5.4.0-42-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.16
Architecture: amd64
CasperVersion: 1.394.3
Date: Wed Jan 20 18:53:53 2021
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/ubuntu.seed boot=casper quiet splash ---
LiveMediaBuild: Ubuntu 18.04.5 LTS "Bionic Beaver" - Release amd64 (20200806.1)
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)