fill problem of hatch area bug

Hi guys，

I'm a rookie here and just come up with a strange bug. I tried to fill in the gap between the two rectangles but it hatched in a strange way. It seems like the hatch area is not defined in a correct way. I tried serveral drawing ways but not OK, google the problem but can not locate the answer. I think it's a common action that will be used a lot so if anyone can give the solution I would very appreciate it.

Follow is the pics I have
       

https://forum.librecad.org/Solid-Hatch-issue-tp5718813.html

Thank you so much for your reply. It's just not decent enough though it works well.
As you mentioned the different math model, I don't think it should be a obvious bug left here since I tried QCAD and it works just fine. May I ask a little more about the algorithem thing of the solid fill because my drawing is almost all about solidfill patterns?

I don't know details about the algorithm thing, I'm not a coder. Lord of Bikes, developer and maintainer, mentioned this in an earlier thread about this issue. All I can say is that it doesn't work in the desired way and it's necessary to cut up a looped shape.
If you are able and interested in helping to fix this issue you are certainly welcome.