Modpack version
1.82a

Issue
The command "/undo_excavation_forced" doesn't require operator (OP) privileges, meaning duplication of blocks
it also keeps blockdata, meaning duplication from chests

The blocks are taken from your inventory if you use the command, seems to be working alright.

Apologies for not seeing (and clarifying) this earlier,
The issue is it will still restore the blocks even if you drop them out of your inventory before running the command.

Should've listed steps:

1. Excavate blocks
2. Drop items onto floor (or put them into a chest)
3. Run /undo_excavation_forced
4. Duplicate blocks (Profit)

Ahh I see. Not much we can do at this point :P

Thank you for the report, I will investigate the issue.