Case of indexing into SteadyState solutions nopt working

[TorkelE]

# Fetch packages
using ModelingToolkitBase
using OrdinaryDiffEqDefault, OrdinaryDiffEqVerner, NonlinearSolve, SteadyStateDiffEq
using ModelingToolkitBase: t_nounits as t, D_nounits as D

# Create model.
@variables X(t)
@parameters p d
eqs = [D(X) ~ p - d*X]
@mtkbuild sys = System(eqs, t)

# Solve problems
sim_conds = [X => 2.0, p => 2.0, d => 0.1]
oprob = ODEProblem(sys, sim_conds, (0.0, 1.0))
ssprob = SteadyStateProblem(sys, sim_conds)
osol = solve(oprob)
sssol = solve(ssprob, DynamicSS(Vern7()))

osol[X] # Fine.
sssol[X] # Fine.
osol[unknowns(sys)[1]] # Fine.
sssol[unknowns(sys)[1]] # ERROR: MethodError: getindex(::SciMLBase.NonlinearSolution{Float64, 1, Vector{Float64}, Vector{Float64