Transparency issue with grease pencil

Here is the same scene viewed from two slightly different angles:

The shadow of the objects on the desk use a material with a fill color that has 0.5 alpha, and at some angle it starts cutting through the desk for some reason. Is this a bug? Is there a way to avoid it? All my gpencil objects use “3D location” as depth order.

I assume the shadowss are drawn with grease pencil on surface? If modeled in geometry and two surfaces are to close to each other there is something called z-fighting. IDK how the grease pencil handle this, but seeing the notes on the desk… quite well. BUT the alpha seem to make some problems. Question: why drawing a shadow with alpha an not just darker (or adding color blend?) in the first place?

Hi @Okidoki I used transparency because I want to move the objects around and for instance if the mug is put partly onto the papers then the hack of drawing with a darker color no longer works. I thought about z fighting so moved up the shadows a bit but still the same result.