Affects Version/s: Minecraft 1.8.1
Fix Version/s: Minecraft 1.8.8
Environment:Windows 7, Java 8 Update 25
First off. It's been in the game since 1.5
Okay - If you want to divide items up using a hopper chain, lets say for a furnace array (see attachments).
This is entirely possible, in fact it works flawlessly... UNTIL you reload the chunks.
What before divided a stack in to 8 in 8 furnaces, now gives one furnace 15 items and the rest around 7 - making it useless!
You can temporarily fix this issue, but it will eventually reoccur
I believe it is caused by a change in the priority of the hoppers, but it is pretty hard to recreate so i could not get closer to the source.
You can check this video by 777static777 for further proof: