diff --git a/src/rulesets/SparseArrays/sparsematrix.jl b/src/rulesets/SparseArrays/sparsematrix.jl
index 12ae76f80..99f0b4ba1 100644
--- a/src/rulesets/SparseArrays/sparsematrix.jl
+++ b/src/rulesets/SparseArrays/sparsematrix.jl
@@ -30,6 +30,7 @@ function rrule(::typeof(findnz), A::AbstractSparseMatrix)
 
     function findnz_pullback(Δ)
         _, _, V̄ = unthunk(Δ)
+        V̄ = unthunk(V̄)
         V̄ isa AbstractZero && return (NoTangent(), V̄)
         return NoTangent(), sparse(I, J, V̄, m, n)
     end
@@ -43,6 +44,7 @@ function rrule(::typeof(findnz), v::AbstractSparseVector)
 
     function findnz_pullback(Δ)
         _, V̄ = unthunk(Δ)
+        V̄ = unthunk(V̄)
         V̄ isa AbstractZero && return (NoTangent(), V̄)
         return NoTangent(), sparsevec(I, V̄, n)
     end
diff --git a/test/rulesets/SparseArrays/sparsematrix.jl b/test/rulesets/SparseArrays/sparsematrix.jl
index ea0cf5199..2a3600619 100644
--- a/test/rulesets/SparseArrays/sparsematrix.jl
+++ b/test/rulesets/SparseArrays/sparsematrix.jl
@@ -77,6 +77,14 @@ end
     I, V = findnz(v)
     V̄ = rand!(similar(V))
     test_rrule(findnz, v ⊢ dv, output_tangent=(zeros(length(I)), V̄))
+
+    # cotangent components may be thunks
+    IA, JA, VA = findnz(A)
+    V̄A = rand!(similar(VA))
+    _, pb = rrule(findnz, A)
+    @test pb((ZeroTangent(), ZeroTangent(), @thunk(V̄A)))[2] == sparse(IA, JA, V̄A, 5, 5)
+    _, pb = rrule(findnz, v)
+    @test pb((ZeroTangent(), @thunk(V̄)))[2] == sparsevec(I, V̄, 5)
 end
 
 if Base.USE_GPL_LIBS # these rrules don't work without CHOLMOD from SuiteSparse.jl