Horizontal bar plots are off center

[Brinkhuis]

Horizontal bar plots are off center while vertical bar plots work just fine.
[Julia 1.7.3 and Gadfly 1.3.4]

using CSV, DataFrames, Statistics, Gadfly

download("https://raw.githubusercontent.com/mwaskom/seaborn-data/master/penguins.csv", "penguins.csv")
penguins = DataFrame(CSV.File("penguins.csv"))

set_default_plot_size(16cm, 12cm)

plot(
    combine(groupby(dropmissing(penguins), [:species, :sex]), :body_mass_g .=> mean .=> :body_mass_g),
    x = "species", 
    y = "body_mass_g", 
    color = "sex", 
    Geom.bar(orientation = :vertical),
    Theme(bar_spacing = 15mm, background_color = "white",)
)

plot(
    combine(groupby(dropmissing(penguins), [:species, :sex]), :body_mass_g .=> mean .=> :body_mass_g),
    x = "body_mass_g", 
    y = "species", 
    color = "sex", 
    Geom.bar(orientation = :horizontal),
    Theme(bar_spacing = 15mm, background_color = "white",)
)