diff --git a/src/physics/autompo/opsum_to_mpo.jl b/src/physics/autompo/opsum_to_mpo.jl
index 1388fe91f9..892ac4a88f 100644
--- a/src/physics/autompo/opsum_to_mpo.jl
+++ b/src/physics/autompo/opsum_to_mpo.jl
@@ -16,7 +16,7 @@ function svdMPO(ValType::Type{<:Number}, os::OpSum{C}, sites; kwargs...)::MPO wh
     return (only(site(t[1])) <= n <= only(site(t[end])))
   end
 
-  rightmaps = fill(Dict{Vector{Op},Int}(), N)
+  rightmaps = [Dict{Vector{Op},Int}() for _ in 1:N]
 
   for n in 1:N
     leftbond_coefs = MatElem{ValType}[]