Why do we see these fine black lines?

[EA101]

First of all, I have to say I love so much Adobe Fresco, because this legendary app encourages me to art. 

But I have a problem. I do vector drawing and why do I see these very thin black lines between two patterns. Am I doing something wrong? I tried other vector pens but I couldn't solve this problem.

I believe this is a problem that concerns everyone.

Can you help me to solve this annoying thing please? 

[Sjaani]

I feel that this comes down to the idea that Fresco does not create true vector lines. So when you zoom in you see the slight rastor line.

[EA101]

Hi Sjaani! thank you very much for your time.

Actually no need to zoom in for see them, but I found some kind of solution to fix this problem.

All these slight rastor lines are weird issue caused by the background color. When I change the background colors, they also change. But if I duplicate the layer, all these black lines disappear, so we just need same two layers. Yes, this is so weird but it works.