Let $L/K$ be a Galois extension of number fields. Consider the natural map 
$$ F: H^1(\operatorname{Gal}(L/K), E(L)) \to \bigoplus_{v \in M_K} H^1(\operatorname{Gal}(L_w/K_v), E(L_{v_L})), $$
where $\operatorname{Gal}(L_w/K_v)$ denotes the local Galois group corresponding to the place $v$.

For an abelian group $M$, let $\hat{M}$ denote its Pontryagin dual.

In this context, the Tate-cohomology group is represented as 
$$ \hat{H}^0(\operatorname{Gal}(L/K),E(L)) = E(K)/(1+\sigma)E(L). $$

According to p214 of the cited paper ([link](https://link.springer.com/article/10.1007/BF02772219)), it's claimed that
$$ \operatorname{\widehat{coker}} F \cong \hat{H}^0(\operatorname{Gal}(L/K),E(L)), $$
but this is asserted without further explanation.

Could you provide some insights or suggest strategies for proving this isomorphism?