I wrote a plug-in for a client that was originally supposed to use Curve bend tool with upper and lower curve.
But once I got it working, it would work the 1st time when I call it when opened with new GIMP.
Everytime after that it would either error saying some weird thing about gimp_resize something which isn't called by me. Other times it would error saying something else always complaining about curve_bend.exe.
So I gave up because the error was too inconsistent.

Does anyone know what's up with that?

Anyways I came up with my own solution by pixel mapping my own bending based on top curve and bottom curve which are paths that can be wider/narrower relative to each other. At first I used vertical lines mapping and used scaling to scale it to the right length and rotate it so that they all work together to be like mapping a surface. But this was really slow. So at the end, I ended up mapping pixel by pixel and using fast pixel operation and it was super fast. so I am happy with that and this is even better than curve bend because curve bend only do top and bottom curves of the same x-coords. And the client was happy with that.

But yeah my point of this post was just to ask WHAT is up with curve bend tool?