Happens when duplicating ANY book

The mod Miner Placement Aid (1.2.1) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event miner-placement-aid::on_player_cursor_stack_changed (ID 35)
Item is not blueprint.
stack traceback:
[C]: in function 'is_blueprint_setup'
miner-placement-aid/control.lua:42: in function 'highlight_should_be_active'
miner-placement-aid/control.lua:104: in function <miner-placement-aid/control.lua:101>

Hey, thanks for the report! :)
It seems that holding any blueprint book from the player's inventory caused a crash.

I released a temporary fix, where books are simply ignored. You can update the mod and the crash shouldn't happen anymore.