Thanks for finding that.
Didnt know the term "sideloading", didnt find anything useful when I searched for some random stuff that kinda described this.
Its mostly about going from yellow to red belts though, the issue happens with red to red also...

Hi,
I dont know if this is a known issue and its not thaaaat bad, I can work around it, but its kind of bugging(hehe) me.
Like seen in the video, the copper plates come from the bottom, turn right and should unload onto the belts coming from the top. Only the upper side of the belt gets taken over ...