Based on several computations I have done, it seems that the second Hurewicz homomorphism $$h:\pi_{2}(X)\rightarrow H_{2}(X;\mathbf{Z})$$ has a habit of being trivial. For instance, this seems to be the case for $X=S^{6}, \mathbf{RP}^{6},$ and $\mathbf{T}^{6}$, as well as for all compact symplectic groups $Sp(n)$, unitary groups $U(n)$, and special unitary groups $U(n)$, as well as the orthogonal groups $O(n)$ for $n\geq 4$ (which are the ones I care about for my problem).
This leaves me wondering: are there any compact, familiar, even-dimensional manifolds (dimension at least $6$) for which the second Hurewicz homomorphism isn't trivial?
If there aren't, would any of you happen to know any less familiar or less elementary examples that fit the bill?
Just take $X=S^2\times T^4$. To obtain such a manifold.