Possible partial fix for `point_id` reconcilation.

app/mutations/point_groups/update.rb

@@ -15,7 +15,7 @@ module PointGroups
     end
 
     def validate
-      validate_point_ids if point_ids.any?
+      validate_point_ids if point_ids.present?
       validate_sort_type
     end
 
@@ -38,19 +38,26 @@ module PointGroups
     end
 
     def maybe_reconcile_points
+      # Nil means "ignore"
+      # []  means "reset"
+      return if point_ids.nil?
+
       # STEP 0: Setup
-      @old_point_ids = Set.new(point_group.point_group_items.pluck(:id))
+      @old_point_ids = Set.new(point_group.point_group_items.pluck(:point_id))
       @new_point_ids = Set.new(point_ids)
       @dont_delete = @new_point_ids & @old_point_ids
       @do_delete = (@old_point_ids - @dont_delete).to_a
 
       # STEP 1: "Garbage Collection" of PGIs that are no longer used.
-      PointGroupItem.where(id: @do_delete).map(&:destroy!)
+      PointGroupItem
+        .where(point_group_id: point_group.id)
+        .where(point_id: @do_delete)
+        .destroy_all
 
       # STEP 2: Create missing PGIs
       @do_create = (@new_point_ids - @dont_delete)
-      PointGroupItem.create!(@do_create.to_a.uniq.map do |id|
-        { point_id: id, point_group_id: point_group.id }
+      PointGroupItem.create!(@do_create.to_a.uniq.map do |point_id|
+        { point_id: point_id, point_group_id: point_group.id }
       end)
     end
   end