UEFI installation of 16.04 x64 fails for custom XFS filesystem

I recently did a reinstall of 16.04 (x64) on my machine that has Win 8.1 preinstalled. My installation configuration for Ubuntu used custom partitioning with partitions for /, swap and UEFI (as used by Windows). The linux partitions were XFS format. The installation failure experienced was specifically around GRUB, which essentially dropped me into a GRUB boot prompt where I was not able to then boot my new Ubuntu install (I was still able to boot Windows). After thrashing around a fair bit, and reproducing the problem in virtualbox, it appears to me that the issue is related to GRUB not being able to read XFS. Grub can read XFS but only if the Grub XFS modules are loaded - which in my case was not working because /boot was on my root partition that was formatted in XFS. The solution I found was to create a separate partition for /boot formatted with EXT2, so that the Grub modules can be accessed.

My question is, am I correct that this was the root cause of the problem and also shouldn't the ISO installation process enforce a grub installation that is going to work with XFS?