I know it's not really an Ubuntu bug, but ZFS on Linux is broken. Try growing a disk in say VMWare or VirtualBox at see ZFS on Linux not knowing how to grow the filesystem.
It's a bug because it actually works in OpenZFS. It's suppose to work, there's commands for it in the ZFS tools. Linux is the only platform where this doesn't work.
Also ignoring that virtualization exists would be a little silly for a modern filesystem. There's features of ZFS that of cause doesn't make sense on virtualized hardware, but things like snapshotting and checksumming are still nice to have.
It would be nice it that was fixed.