minreal returns system of order 21 instead of order 5. about controlsystems.jl HOT 2 CLOSED

julia> s = tf("s")
TransferFunction{Continuous, ControlSystemsBase.SisoRational{Int64}}
s
-
1

Continuous-time transfer function model

julia> g = 1/(s-1)^4
TransferFunction{Continuous, ControlSystemsBase.SisoRational{Int64}}
            1
--------------------------
s^4 - 4s^3 + 6s^2 - 4s + 1

Continuous-time transfer function model

julia> g_tot_tf = [ 1/s*g; g; s*g; s*s*g; s*s*s*g ];

julia> g_tot = ss(g_tot_tf);

julia> g_tot.nx
21

julia> g_tot_m = minreal(g_tot);

julia> g_tot_m.nx
17

julia> g_tot_m = minreal(g_tot, 1e-12);

julia> g_tot_m.nx
5