When you throw an item through a nether portal in the overworld and the chunks, where the opposite portal stands, aren't loaded, the server will crash.
We tested it twice, when somebody was in the nether - the server didnt crash ; when nobody was in the nether - the server crashed when we threw an item through the portal.
Environment
Minecraft Version: 1.8.1
Operating System: Linux (amd64) version 3.10.23-xxxx-std-ipv6-64
Java Version: 1.8.0_25, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
java version "1.8.0_25"
Java(TM) SE Runtime Environment (build 1.8.0_25-b17)
Java HotSpot(TM) 64-Bit Server VM (build 25.25-b02, mixed mode)
Thank you for your report.
However, your ticket has been resolved as a duplicate.
This issue has been linked to the original bugreport: MC-73866. You can find or add further information on that report.
Please search before reporting any bugs, as it's likely that one exists already.