1) Open Material samples, Eye scene
2) Select any eye, zoom in and remove its Iris normal
3) Notice the change
4) Switch from shadergraph to HDRP Eye shader
5) Again, remove Iris normal
6) Notice there is no change

Expected: Shadergraph Eye shader in the sample would match HDRP Eye shader
Result: HDRP Eye shader does not consider Iris normal map

Even simply switching between Eye and Shadergraph Eye you can see the difference. Bonus video