diff --git a/src/plot.jl b/src/plot.jl
index 3e6dd9a3..8968df8c 100644
--- a/src/plot.jl
+++ b/src/plot.jl
@@ -84,7 +84,7 @@ function plot(plt1::Plot, plts_tail::Plot...; kw...)
     # TODO: replace this with proper processing from a merged user_attr KW
     # update plot args, first with existing plots, then override with d
     for p in plts
-        _update_plot_args(plt, p.attr)
+        _update_plot_args(plt, copy(p.attr))
         plt.n += p.n
     end
     _update_plot_args(plt, d)