Cirq: Result of rotating qubit measurements never come [0 1] or [1 0 ], always come as [0,0] or [1,1]

I am creating a 2 qubit entangled state:

    def density_matrix_chsh(i, j, qs):
        circuit = chsh_circuit(i, j, qs)
        return cirq.final_density_matrix(circuit, qubit_order=qs)


    def chsh_circuit(i, j, qs):
        return cirq.Circuit(cirq.H(qs[i]), cirq.CNOT(qs[i], qs[j]))


    qs = [a, b]

    state = density_matrix_chsh(0, 1, qs)

Then I am applying rotation for maximum violation:

th = np.pi/(-2)
th1 = np.pi/(4)
th2 = 0 
random_angles = []
newlist = []
b_big = cirq.kron(cirq.unitary(cirq.ry(th)),cirq.unitary(cirq.ry(th)))
results = []
for choosen in itertools.product([th2, th1], repeat=2): 
        random_angles.append(choosen)
for i in range (1000):
    choosen_combination = random.choice(random_angles)
    a_big = cirq.kron(cirq.unitary(cirq.rz(choosen_combination[0])),cirq.unitary(cirq.rz(choosen_combination[1])))    
    rotated_state = b_big @ a_big @ state @ b_big.conj().T
    measurement_rotated = cirq.measure_density_matrix(rotated_state,indices=[0, 1])
    print("measuring qubits ",measurement_rotated)
    qubit_result = measurement_rotated[0]
    results.append(qubit_result)

For instance here I tried 1000 times and both qubits are either 0 or 1 at the sma time but I could never see one of them 1 and the other one is 0 after measurement. Probably I am doing something wrong and I can’t see
Thanks for helps

import itertools
import random
import cirq
import numpy as np

def chsh_circuit(i, j, qs):
    return cirq.Circuit(cirq.H(qs[i]), cirq.CNOT(qs[i], qs[j]))

qs = cirq.NamedQubit("a"), cirq.NamedQubit("b")

th = np.pi/(-2)
th1 = np.pi/(4)
th2 = 0
random_angles = []
newlist = []
b_big = cirq.Circuit(cirq.ry(th)(qs[0]), cirq.ry(th)(qs[1]))
results = []
for choosen in itertools.product([th2, th1], repeat=2):
        random_angles.append(choosen)

print(random_angles)
for i in range (1000):
    choosen_combination = random.choice(random_angles)
    a_big = cirq.Circuit(cirq.rz(choosen_combination[0])(qs[0]),
                         cirq.rz(choosen_combination[1])(qs[1]))
    rotated_state = cirq.Circuit(chsh_circuit(0,1, qs), a_big, b_big, cirq.measure(*qs))
    res = cirq.Simulator().run(program=rotated_state, repetitions=1)
    print("measuring qubits ",res.measurements)