Problem/Bug Dropped items disappearing.

For some reason, dropped items are disappearing unless you're an Admin.
I have NO clue what so ever what might cause this.

These are the plugins my server is running atm:
http://imgur.com/1vNVRFr

 

It seems like you're running quite a few plugins there. The best option in these cases is to disable your plugins and then enable them one at a time to figure out which plugin is causing this. Once you have identified the plugin you can check to see if any permission nodes are available for it or simply remove it.

 

Yes, as scrollbar said, you should troubleshoot your plugins and find out which one is causing it. Take a look at this plugin troubleshooting video, it will help you quickly and efficiently troubleshoot your plugins instead of doing them one by one.