$\text{Perfect square} + \text{Perfect cube}$

Case 1:

$2^2 + 2^3 = 12 \longrightarrow \text{Even}$

Case 2:

$3^2 + 4^3 = 73 \longrightarrow \text{Odd}$

Hence the answer is $\color{#20A900} \boxed{\text{Sometimes true, sometimes false}}$

64+64=128 It is sometimes true 9+64=73 It is sometimes false