I'm using this mod together with the AAI Loaders mod by Earendil: https://mods.factorio.com/mod/aai-loaders

When using a quality down-binning chest with red or blue loaders (throughput 30 or 45 items/s) sometimes an items slips through without getting "down-binned". My feeling is that this always happened when not watching or actively trying to reproduce it. However, I've solved this by applying a filter to the outbound loader of only letting through items of the desired quality. That's much better than a jammed production line.

Looks like loaders are sometimes able to bypass the implementation's requirement that an item exist within a down-binner for at least 1 tick. Added a note to the description.

That makes sense. Also thanks a lot for your mod! It's such a relief when handling quality ore, stone, ice or solid fuel on Fulgora! I think this is how the quality mechanic should work - being able to tell a machine that it can also use input of any higher quality for the recipe.