Factorio Forums

I was attempting to make a controlled science mixer to use Sushi Science in .15, but there are some inconsistancies with how circuits control sideloading belts. With yellow belts they sometimes put an extra item on the belt, while red belts only ever put as much as I want.
This is a video i made showing the setup, first with red to show the desired result and then with yellow to show the problem.
https://youtu.be/Ru8Gsm8tPCY
I also included the save file, there were no mods or anything enabled on this map

There is no problem with the belts as far as I can see.
Your setup needs 3 ticks to react to the belts changing contents. If you have 2 lanes, the top belt pushes items too fast before it is turned off.
Try using just 1 lane.