plot(sol(0:19)): ERROR: type DiffEqArray has no field indepsym #262

julia> plot(sol(0:19))
ERROR: type DiffEqArray has no field indepsym
Stacktrace:
 [1] getproperty(x::DiffEqArray{Float64, 2, Vector{Vector{Float64}}, UnitRange{Int64}, ODESystem, ModelingToolkit.var"#566#generated_observed#528"{Bool, ODESystem, Dict{Any, Any}}, Vector{Float64}}, f::Symbol)
   @ Base ./Base.jl:37
 [2] macro expansion
   @ ~/.julia/packages/RecursiveArrayTools/vIA4h/src/vector_of_array.jl:444 [inlined]
 [3] apply_recipe(plotattributes::AbstractDict{Symbol, Any}, VA::AbstractDiffEqArray)
   @ RecursiveArrayTools ~/.julia/packages/RecipesBase/z10lo/src/RecipesBase.jl:300
 [4] _process_userrecipes!(plt::Any, plotattributes::Any, args::Any)
   @ RecipesPipeline ~/.julia/packages/RecipesPipeline/XxUHt/src/user_recipe.jl:38
 [5] recipe_pipeline!(plt::Any, plotattributes::Any, args::Any)
   @ RecipesPipeline ~/.julia/packages/RecipesPipeline/XxUHt/src/RecipesPipeline.jl:72
 [6] _plot!(plt::Plots.Plot, plotattributes::Any, args::Any)
   @ Plots ~/.julia/packages/Plots/p3KMq/src/plot.jl:223
 [7] #plot#188
   @ ~/.julia/packages/Plots/p3KMq/src/plot.jl:102 [inlined]
 [8] plot(args::Any)
   @ Plots ~/.julia/packages/Plots/p3KMq/src/plot.jl:93
 [9] top-level scope
   @ REPL[74]:1

julia> independent_variables(ss.sc)
1-element Vector{SymbolicUtils.BasicSymbolic{Real}}:
 t