Steps to reproduce:
1. Open the attached user's project "U2020_3_48-OnGuiBehaviorLeak.zip"
2. Open the "SampleScene.unity" Scene
3. Enter Play Mode
4. Open Profiler and enable Memory Profiler Module
5. Observe the memory increase

Expected results: no memory leak when using OnGUI
Actual results: Memory leak when using OnGUI (See attached "Snapshot Comparison.png")

Reproducible with: 2021.3.32f1, 2022.3.13f1, 2023.2.0f1, 2023.3.0a14

Reproducible on: Windows 10
Not reproducible on: No other environment tested

Notes:
-A MonoBehavior with "void OnGUI()" in it is all that is needed. A GameObject is dynamically created by calling a new GameObject and the OnGUI component is added then the GameObject is destroyed, thus memory increases.
-Issue is reproducible in Player