How to combine polynomials in matrix operations in Sympy?

I'm doing some matrix operations, sometimes involving matrices whose entries have constant values.

But for some reason, I cannot get the matrix operation to combine the results into a single polynomial, even when the result is simple. for example, consider the following:

from sympy.matrices import *
import sympy

x= sympy.symbol.symbols('x')

Poly_matrix = sympy.Matrix([[sympy.Poly(x, x)],[sympy.Poly(x, x)]])
constant_matrix = sympy.Matrix([[0,1]])
constant_matrix_poly = constant_matrix.applyfunc(lambda val: sympy.Poly(val, x))

# this doesn't combine them
result1 = constant_matrix * Poly_matrix
print result1
>>>> Matrix([[Poly(0, x, domain='ZZ') + Poly(x, x, domain='ZZ')]])

# even THIS doesn't combine them when I convert the constants to Polynomials 
result = constant_matrix_poly * Poly_matrix
print result
>>>> Matrix([[Poly(0, x, domain='ZZ') + Poly(x, x, domain='ZZ')]])

The problem with this, is that when I try to extract the expression, and turn this result into a different polynomial, I get the following error:

# This is where the trouble starts
sympy.Poly(result[0].as_expr(), x)
sympy.Poly(result1[0].as_expr(), x)

And the resulting error is a long traceback, ending with:

PolynomialError: Poly(x, x, domain='ZZ') contains an element of the set of generators.

To be even more specific, it has trouble with result[0].as_expr() because it cannot convert it to an expression using as_expr(), even though it is still an object of type Poly, so it can still use the method as_expr().

Why is it that these polynomials do not automatically get combined into one?
Or is there another way for me to call sympy.Poly(result[0].as_expr(), x)?

EDIT: Here are some questions with a similar error (although sometimes caused by something different):
sympy: PolynomialError: cos(a) contains an element of the generators set Sympy Error when using POLY with SQRT

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