Describe the bug
When placing a barrel from https://www.curseforge.com/minecraft/mc-mods/stockpile next to a conveyor, MC crashes.

https://paste.ee/p/Jt3Q9

java.lang.IllegalArgumentException: You should never test an IItemFilter with an empty stack!

To Reproduce
Place a barrel from stockpile in front of a conveyor, so the barrel gets the output of the conveyor

Expected behavior Optional
MC not crashing

Version of the (please complete the following information):
MC 1.14.4
stockpile-1.1.0+1.14.4.jar
UnitedConveyors-0.0.1.jar (built from source)
fabric-api-0.3.2+build.218-1.14.jar

Additional context Optional
Add any other context about the problem here.

Hm, this looks like a function of LBA's item filter system. It doesn't like having an empty item stack tested against a filter, for some reason. I don't think it's right of it to throw, though.