Lit Layered doesn't handle semi transparency?

I’m trying to use the HDRP/Lit Layered to merge textures together.

Here is my first case, merging two gradient to transparent together:
h.png and v.png
And here is my set up and result, Material set as transparent:

You can see a visible fully transparent vertical line which shouldn’t be there.

Second case: Material is set to opaque this time with red color as main layer

The layer 1 semi transparency is completely ignored.

Did I miss an option somewhere so that merging is smooth?

Best regards

Bump. No one knows about this issue? It seems pretty flagrant to me.

OK so after a reply on Discord, layered textures are ignoring alpha channel so we need to use the layer mask which RGB channels are masks for layer 1, 2 and 3 while the alpha is the mask for the main layer. It was a bit confusing but it makes sense now. Also, since masks are packed together, tiling and offset are linked on each layers.