1. Open attached project "ProfilerInstances 2.zip" and scene "SampleScene"
2. Open Memory Profiler by going Window>Analysis>Profiler>Memory
3. Enter and exit Play Mode repeatedly
4. In Profiler window's Memory tab, observe how the number of Textures, Meshes, and Total Objects In Scene is getting higher after every new play
5. In Hierarchy window, disable or delete Canvas and EventSystem GameObjects
6. Enter and Pause Play Mode, observe numbers in Profiler again

Expected result: The number of Textures, Meshes, and Total Objects In Scene stays the same on every new play
Actual result: The number of Textures, Meshes, and Total Objects In Scene is increasing with every new play except when the Canvas and EventSystem GameObjects are disabled

Reproducible with: 2018.4.33f1, 2019.4.25f1, 2020.3.8f1, 2021.1.6f1, 2021.2.0a16

Note:
Inconsistently, the number of Textures, Meshes, and Total Objects still increases when the Canvas and EventSystem GameObjects are disabled/removed.