The licensee has also provided an explanation as to why this issue occurs + guidance for a potential fix. Please see the UDN for more details.

Steps to Reproduce
  • Open the licensee provided project here - [Link Removed]
  • Expand the 'Content Drawer', double click on M_MaterialLayerSwapTestBase_Inst2, directly under Content/
  • Observe the material has two non-background layers, BlueOrPink and YellowOrGreen, the topmost layer being BlueOrPink. Note that parameters have been setup so that the BlueOrPink layer is blue in the parent material instance but pink in M_MaterialLayerSwapTestBase_Inst2, and the YellowOrGreen layer is yellow in the parent material instance but green in M_MaterialLayerSwapTestBase_Inst2.
  • Now, swap YellowOrGreen with BlueOrPink. Observe that the material layers seem to have been swapped correctly (YellowOrGreen is now the topmost layer and its BaseColor override is green). Note that the thumbnails may not refresh after the swap, but you can hover the mouse over them to get them refreshed.
  • Now, swap BlueOrPink with YellowOrGreen again. This time the material layers haven't been swapped correctly: The topmost layer is named BlueOrPink, but its BaseColor is green, and the layer below is named YellowOrGreen but BaseColor is pink.

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ComponentUE - Rendering - Materials
Affects Versions5.2
CreatedMar 6, 2023
UpdatedMar 6, 2023