Looks like this is only triggering with on_built_entity and on_robot_built_entity, which misses several ways lamps can be built like god or creative mode. Can you add script_raised_revive and script_raised_built?

Also just got this error.
The mod Lamps on Map (0.0.3) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event lampsonmap::on_tick (ID 0)
invalid key to 'next'
stack traceback:
[C]: in function 'for iterator'
lampsonmap/control.lua:384: in function 'save_to_global'
lampsonmap/control.lua:490: in function <lampsonmap/control.lua:476>