Hi OSTexo, I think that weird shape is a bug that I can do something about, it seems to be triggered when the "chord line" connecting the two sides is fairly slanted compared to the edge tangent at that point. It tries to use the chord line as an indicator direction for which side to orient towards but it looks like that's not so good to use when it gets slanted basically.

I think I can do something about that part, but there is a larger problem remaining for this type of sharp trailing edge thing which is that the blend is trying to do 2 different things at the sharp discontinuity area, and it doesn't really help that the shapes are on the same plane there, they're trying to be smooth to 2 different shapes right there. I think that the blend mechanism would need a pretty substantially different strategy in order to handle those sharp areas.

So I'm going to see what I can do about the sudden internal shift thing, that's probably fixable. But it will probably work better for a planar sections blend to avoid the sharp discontinuity on the trailing end and instead have a small tightly bent corner (which in other kinds of cases tends to be bad, but in this situation it's probably needed though, since "Planar sections" behaves quite differently than things that come away perpendicular).

Some kind of corner patch construction like you have on the other side may be a better strategy for a sharp trailing edge... Maybe if the blend would sort of have an "extended rail" type of shape more like how filleting happens that might work for that kind of thing.

- Michael