Skin modifier in 2.8

Hi~ I wanted to use the skin modifier today (wanting to create a tree following a tutorial), but got stuck right at the begining.

So in Blender 2.79, when I use the skin and subdivision surface modifiers, I get the result I want: Some kind of somewhat spheric mesh.

But with 2.8, this is what I get:

So I’ve been looking around, but haven’t really been able to find anything. Is it how it’s supposed to look like in 2.8? If yes, how to you get rid of the square shape on top, I don’t need it?! And if not… Why is it like and this and how do I solve it?

I’m fairly new to Blender so this might seem like a silly question… Anyway, I hope I didn’t post this in the wrong part of the forum.

Hi DaisyCat,

With a plain cube and no changes or selections in edit mode, this is the result I get:

.

Have you edited the cube in any particular way?

Dj.

Hi, thank you for your reply.

What I did was merging the cube’s vertices at center to get only one, then I applied the skin modifier, which gave me a cube again. But then when I added the subdivision surface modifier, it gave me this weird shape instead of giving me something like in 2.79 version:

It is a bug. Behavior should be same as in 2.79.
But here, a unique vertex marked as root seems to produce that.
You can extrude the vertex and bug should disappear.

Oh wow, it really worked. And it was so easy…
Thank you very much !!