My admins copy the buildings, and when pasting them, it only pastes 1/2 the building, and many missing parts. Also /undo is not doing anything. Edit* After some testing, the plugin will paste old builds built from older maps, and also undo works fine on the old map builds as well. New builds built on this map will not copy/paste correctly.

Are there any errors in the console (server*)?

Thanks for replying Misticos. My admins told me about this, so I will get done more testing and get back to you shortly. 

Merged post

Hello @misticos , we did some testing and had varying results. The build was for next map, a Christmas town. We found if it has Deluxe Christmas Lights and Double Doorway Festive Garland, it wont paste properly, and give this error.  It could be other christmas items as well.

(12:40:32) | Exception while calling NextTick callback (InvalidCastException: Specified cast is not valid.)
  at Oxide.Plugins.CopyPaste.PasteLoop (Oxide.Plugins.CopyPaste+PasteData pasteData) [0x00ea1] in <cba0d0f34ab3465c8e715a797211c888>:0 
  at Oxide.Plugins.CopyPaste+<PasteLoop>c__AnonStorey5.<>m__0 () [0x00000] in <cba0d0f34ab3465c8e715a797211c888>:0 
  at Oxide.Core.OxideMod.OnFrame (System.Single delta) [0x00051] in <bae5f1223fce49c493b01571c99dce02>:0​

Right, this should be these entities - thanks for the report.

I hope it helps! Thank you! 

I told him this last year. xD Deluxe lights have always broken pastebacks.

You gotta go into the data file for the structure in Notepad++ and remove the bits with the deluxe lights.