I'm using Crackpack 1.5.1.0 with RefinedRelocation 1.0.4e. I'm not sure if this one is fixed in newer versions, or that it doesn't occur when using this mod in isolation? See two example setups here:

Basically, I connect a normal chest to a sorting interface using some piping system (tested with (Thermal Expansion) ItemDuct and (Extra Utilities) Transfer Node). I will place some item(stack) in the chest and won't change anything on the sorting interface. The piping system transfers some items into the sorting interface. Then, I place a sorting chest next to the sorting interface, and setup a whitelisting filter for the item type I placed in the first chest. The itemstack that was transferred to the sorting interface will be placed into the sorting chest over and over, roughly every second or so?

What may be important in addition is that the order of these events mattered. I have experimented a little and what seemed to be crucial is that the sorting interface needs to be placed before the sorting chest. No items get transferred to sorting chests placed before, duplication only happens for sorting chests placed after.

For completeness sake: the whitelist content didn't seem to matter, as long as it included in some way the item that was transferred to the sorting interface.

Hope this helps to find what caused this! Thanks a bunch in advance, and thanks so much for this mod in general :)

Does not appear to appear in the latest snapshot of Refined Relocation, so I'm guessing this was fixed; although I may be missing something.

@Beyonix: Could you test with the latest version of RR from the buildserver and see if your setup still causes itemstack duplication? If you don't want to / have time to test, could you post screenshots of each sorting GUI?

Thanks for getting back to me this fast! Testing with a newer version would take me some time, but I can provide the screenshots immediately. The filtering GUI for both setups is identical, so here I will provide just one.

The sorting interface is unmodified after placement:

This works for all (four) item types I have tested, but let's take the example of placing gold in the 'source' chest. If you place the sorting chest after the sorting interface, I consistently get the duplication for:

but also for:

As a last note: If I disable the filter that whitelists that item, the duplication halts. If I reenable it, duplication starts again. Hope this helps!

This seems odd to me, as the sorting interface should not accept items with an empty whitelist. Does it do so for you?

This has indeed been fixed since 1.0.5d! Thanks for the informative bug report! I'm not sure when the Crackpack will be updated. The pack creator of the pack is aware that this issue exists and has been fixed, so I expect him to update some time soon!