When blueprinting or copying an Assembling Machine 2 or 3, Foundry, or Electromagnetic Plant, whether the rotation of fluid connections is copied or not depends on the selected recipe. If it has no recipe selected or a recipe that doesn't involve fluids, the rotation isn't copied. If it has a recipe with fluids selected, the rotation is copied.
That has been the case for a long time, but it never used to matter because recipes would be set before blueprinting stuff. Now that recipes can be changed by circuit or blueprint parameters, it's far more likely that a blueprint will be made with no recipe or a non-fluid recipe selected and then given a recipe with fluids after placement.
Reproduction steps:
The attached save makes it easy to see. Otherwise:
- Place an Assembling Machine 2 or 3, Foundry, or Electromagnetic Plant.
- Set the recipe to one with a fluid input or output.
- Rotate the machine and set up the pipe connections.
- Set the recipe to one with no fluids.
- Copy and paste the setup elsewhere.
- Set the recipe back to one with a fluid.
- The direction of fluid connections is reset to the default on the copy, but the original remembers the way it was rotated.