That pretty much sums up the bug I think.
I discovered that when I followed shanaqui’s advice to use custom goals to create a whittle down trello goal. After I did that I fired up the visual road editor to move the change of rate from + to - further ahead in time.
Which totally worked. As in: It did not care at all about the akrasia horizon.
In contrast the old textual one does care about the akrasia horizon.