Fail to hightlight code

[nandoconde]

I just received this error, it might help.

failed to highlight code, Base.InvalidCharError{Char}('\xcf')

I provide here the context in which I received it:

In _add_degree(F, ω, f_init) at C:\Users\ferna\Documents\repos\PPS\src\math\fosterfitting.jl:401
 401  function _add_degree(F, ω, f_init)
 402      # To Foster_Π
 403      foster_form = Foster_Π(f_init)
 404      # Polynomials
>405      ω_var = Polynomial(Float64[0,1], :ω)
 406      P = minusprod(foster_form.ω_z, ω_var)
 407      Q = minusprod(foster_form.ω_p, ω_var)
 408      foster_form.zero_zero ? (P = P * ω_var) : (Q = Q * ω_var)
 409      # Add next degree(either zero or pole)
 410      if degree(P) < degree(Q)
 411          return _extra_zero(F, ω, foster_form)
 412      else
 413          return _extra_pole(F, ω, foster_form)
 414      end
 415  end

About to run: (getindex)(Float64, 0, 1)
1|debug> n
failed to highlight code, Base.InvalidCharError{Char}('\xcf')
In _add_degree(F, ω, f_init) at C:\Users\ferna\Documents\repos\PPS\src\math\fosterfitting.jl:401
 401  function _add_degree(F, ω, f_init)
 402      # To Foster_Π
 403      foster_form = Foster_Π(f_init)
 404      # Polynomials
 405      ω_var = Polynomial(Float64[0,1], :ω)
>406      P = minusprod(foster_form.ω_z, ω_var)
 407      Q = minusprod(foster_form.ω_p, ω_var)
 408      foster_form.zero_zero ? (P = P * ω_var) : (Q = Q * ω_var)
 409      # Add next degree(either zero or pole)
 410      if degree(P) < degree(Q)
 411          return _extra_zero(F, ω, foster_form)
 412      else
 413          return _extra_pole(F, ω, foster_form)
 414      end
 415  end

About to run: <(getproperty)(Foster_Π{Float64}(false, -2.3237358489231066e-8, [4.00501897174773e11], Float64[]), :�...>
1|debug>

It can be seen in the last line that something is missing. It should be a lower case omega (ω).