diff --git a/Project.toml b/Project.toml
index 62c8e76ef..55827d7a9 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "Tapir"
 uuid = "07d77754-e150-4737-8c94-cd238a1fb45b"
 authors = ["Will Tebbutt and contributors"]
-version = "0.1.2"
+version = "0.1.3"
 
 [deps]
 ChainRulesCore = "d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4"
diff --git a/src/interface.jl b/src/interface.jl
index 3e35018fb..f161583c8 100644
--- a/src/interface.jl
+++ b/src/interface.jl
@@ -10,7 +10,7 @@ function value_and_pullback!!(rule::R, ȳ::T, fx::Vararg{CoDual, N}) where {R,
     out, pb!! = rule(fx...)
     @assert _typeof(tangent(out)) == T
     ty = increment!!(tangent(out), ȳ)
-    v = copy(primal(out))
+    v = deepcopy(primal(out))
     return v, pb!!(ty, map(tangent, fx)...)
 end