diff --git a/scenes/ui/workbench_panel.gd b/scenes/ui/workbench_panel.gd
index b7cf4de..0bfe0b5 100644
--- a/scenes/ui/workbench_panel.gd
+++ b/scenes/ui/workbench_panel.gd
@@ -292,9 +292,10 @@ func _make_bill_row(bill: Bill) -> VBoxContainer:
 	mode_btn.item_selected.connect(func(idx: int) -> void:
 		bill.mode = idx as Bill.Mode
 		Audit.log("workbench_ui", "%s: bill mode → %d" % [current_workbench.label_text, idx])
-		# Repopulate so conditional rows update; OptionButton state survives because
-		# we set mode on bill before the rebuild, and the new row reads bill.mode.
-		_populate_bills()
+		# Defer the rebuild — we must NOT free mode_btn while its item_selected
+		# signal is still emitting (instant crash).  call_deferred runs the
+		# repopulate after the signal frame completes.
+		call_deferred("_populate_bills")
 	)
 	mode_row.add_child(mode_btn)
 
@@ -366,7 +367,8 @@ func _make_bill_row(bill: Bill) -> VBoxContainer:
 			current_workbench.label_text,
 			bill.recipe.id if bill.recipe != null else "null"
 		])
-		_populate_bills()
+		# Defer — same reason as mode_btn: don't free this button mid-emit.
+		call_deferred("_populate_bills")
 	)
 	remove_row.add_child(remove_btn)