Non-solid blocks from addons still cause fence/walls to connect

Any created addon block causes fence/wall to connect independent of its hitbox, transparency, etc.

Steps to Reproduce:

Load an Addon that includes a custom block that is not a full-size block, for instance, a slab with a partial collision box.

Place the slab and surround it by any configuration of walls or fences and observe. Then, replace the slab with a vanilla slab and observe.

What happens:

The fences and walls act as if the custom slab is a full block, and readily connect to it as would be expected of a full block.

Subsequently, the vanilla slab does not cause the fences and walls to connect, as intended.

What I expect to happen:

A partial collision box dictates that the block does not have a solid side, so walls and fences shouldn't attempt to connect to it.