How to reproduce:
1. Open the attached "1310512_Repro" project
2. Open the Scene "TestScene"
3. Open the Profiler (Window->Analysis->Profiler)
4. Make sure the Profiler is set to record the Playmode and recording is enabled
5. In the Profiler enable the GPU Module (top left of the profiler Profiler Modules-> check GPU Usage)
6. Enter the Play Mode
7. In the Project window select the "TestLeaves" Material
8. In the Inspector change the Shader from "HDRP/Lit" to "Shader Graphs/LeafTest"

Expected results: The performance stays the same
Actual results: The performance drops significantly

Reproducible with: 10.3.1 (2020.2.5f1) 11.0.0 (2021.1.0b7, 2021.2.0a4)
Couldn't test with: 8.3.1 and earlier because the Shader Graph breaks and on a fresh project the difference was too small to tell exactly if it exists