[0.15.8] minor issue/intended?. underground belt

[darkmtbg2]

Downgrading (tested from fast to normal) underground belts doesnt fast replace the output of the incase the underground belt is the lenght that the lower tier of belt can support is this intended behavior?(i assume it is but i kinda threw me off)

[posila]

Thanks for the report.
It works as programmed, but since you reported it in hours after this being an issue in vanilla, I supposed it should be changed.
Fixed for 0.15.10