Image explains it best, the jungle planks are connected at the top but not at the side

I'm using Stay True.

This is the properties file:

matchBlocks=birch_planks dark_oak_planks crimson_planks warped_planks
method=overlay
tiles=0-16
connectBlocks=acacia_planks

Textures in question:

Maybe it makes sense to make this optional? I could imagine a slight performance loss and/or a behavior that not everyone expects.

Well this behavior isn't ideal, it does match Optifine

Well this behavior isn't ideal, it does match Optifine

IMO this should still be implemented if possible. Maybe with it being off by default.

You could reuse the innerSeams tag that is available for ctm as a way to change this