Let $\mathcal{A} \subset \mathcal{K}$ be two locally presentable categories. $\mathcal{A}$ reflective and closed under filtered colimits. Then $\mathcal{A}$ is a small-orthogonality class. Let $R:\mathcal{K}\to \mathcal{A}$ be the reflection. Let $G$ be a dense generator of $\mathcal{K}$ consisting of objects not belonging to $\mathcal{A}$. Can we conclude that $\mathcal{A}$ is the small-orthogonality class with respect to the set of maps $\{\eta_g:g\to Rg \mid g\in G\}$ ?

I think that the answer is negative in full generality and I would like to see a counterexample.

Note: I have edited my question to remove the case $G\subset \mathcal{A}$.