diff --git a/changelog.txt b/changelog.txt
index 615ca0ac..78e3a10a 100644
--- a/changelog.txt
+++ b/changelog.txt
@@ -1,4 +1,9 @@
 ---------------------------------------------------------------------------------------------------
+Version: 3.1.4
+Date: ????
+  Changes:
+    - Fixed that assembling machine fluidbox connections were referenced instead of copied. Resolves https://github.com/pyanodon/pybugreports/issues/1551
+---------------------------------------------------------------------------------------------------
 Version: 3.1.3
 Date: 2026-07-16
   Changes:
diff --git a/prototypes/updates/entity-updates.lua b/prototypes/updates/entity-updates.lua
index 3965cd78..83136009 100644
--- a/prototypes/updates/entity-updates.lua
+++ b/prototypes/updates/entity-updates.lua
@@ -65,7 +65,7 @@ local burner = {
 --modify assembly machine 1
 data.raw["assembling-machine"]["assembling-machine-1"].crafting_speed = 1
 data.raw["assembling-machine"]["assembling-machine-1"].energy_source = table.deepcopy(burner)
-data.raw["assembling-machine"]["assembling-machine-1"].fluid_boxes = data.raw["assembling-machine"]["assembling-machine-2"].fluid_boxes
+data.raw["assembling-machine"]["assembling-machine-1"].fluid_boxes = table.deepcopy(data.raw["assembling-machine"]["assembling-machine-2"].fluid_boxes)
 table.insert(data.raw["assembling-machine"]["assembling-machine-1"].crafting_categories, "crafting-with-fluid")
 
 --modify assembly machine 2