Happens when selecting a copper patch near a source of water:
Factorio: 18.27
OP:1.1.4

Error while running event PlannerCore::on_tick (ID 0)
on_built_entity (ID 6) (6) can't be raised through script.
stack traceback:
PlannerCore/OB_helper.lua:171: in function <PlannerCore/OB_helper.lua:124>
(...tail calls...)
PlannerCore/OB_stages.lua:174: in function '?'
PlannerCore/OB_stages.lua:291: in function 'stage_function'
PlannerCore/planner-core.lua:32: in function 'placement_tick'
PlannerCore/planner-core.lua:123: in function <PlannerCore/planner-core.lua:105>
stack traceback:
[C]: in function 'raise_event'
PlannerCore/OB_helper.lua:171: in function <PlannerCore/OB_helper.lua:124>
(...tail calls...)
PlannerCore/OB_stages.lua:174: in function '?'
PlannerCore/OB_stages.lua:291: in function 'stage_function'
PlannerCore/planner-core.lua:32: in function 'placement_tick'
PlannerCore/planner-core.lua:123: in function <PlannerCore/planner-core.lua:105>

The error seems to be a fault of the planer core.
https://mods.factorio.com/mod/PlannerCore/discussion/5ecfd0546ef132000c2e340e

Thanks, fixed in PlannerCore 0.2.3

Confirmed, that fixed it, thanks a bunch!