[Reflection] The wall doesn't lock light's specular highlight

Hi Guys

I have a question, the wall doesn’t lock light’s specular highlight. As you can see picture below, there is a point light inside the house, but the water still reflect the highlight. The wall has thickness, and it also happens on directional light.

But the highlight doesn’t appear on the PlanarReflection.

Anyone know what is going on here?

Thanks