Setting ZDOTDIR to XDG_CONFIG_HOME/zsh breaks ZSH support

Apologies if this is expected behaviour.

In order to keep my configuration files concise, and declutter my home directory, I have zsh configured like this:

cat ~/.zshenv
# XDG
export XDG_CONFIG_HOME="${HOME}/.config"
export XDG_CACHE_HOME="${HOME}/.cache"
export XDG_DATA_HOME="${HOME}/.local/share"
export XDG_STATE_HOME="${HOME}/.local/state"

export ZDOTDIR="${XDG_CONFIG_HOME}/zsh"

Which results in .zshrc, presumably other zsh config files, not being sync'd via mackup backup.

Would you be open to supporting this configuration?