Success! I have fixed the item download bug. Not just on other maps but for fjordur too. I'm not 100% on the fix cause I changed multiple things at the same time but I can now download things uploaded on fjordur to any map. This includes dinos, items, and characters.
After all players were uploaded I stopped the server, swapped it to island and started server. Went to an obelisk and was unable to download items, the server crashed.
With the server shut down this time I unchecked all admin options in the general settings for server(admin log and such) and checked prevent item download. Then saved. Then unchecked prevent item download and saved again. Loaded the server up and went to an obelisk and was able to download items. Having seen this I re-uploaded everything, stopped server and swapped back to fjordur.
Reloaded server and went to an obelisk and was able to download and upload.
Swapped back to island and everything is now peachy.
Please share this with nitrado staff and any others who encounter the same problem, as it fixed it. My best guess is somehow the prevent item download was set to on but showing off, so manually toggling it reset the config. Either that or removing all admin features for logs bogged it down.