This may be intentional, but I don't think so. I have recreated the situation with creative mode mods to more clearly illustrate it.
It came about when I was attempting to drain an old belt while having the new belt ready to go by using splitter input priority. I was only lifting off of one side of the output as shown.
Instead of first draining the priority input, it only used one half of the belt it then began taking from low priority input.
I expected it to completely empty the priority input before taking resources from the low priority side, regardless of which half of the belt materials are on.
Thanks!
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