Steps to reproduce:
1. Open new project
2. Open frame debugger and enable it
3. select somthing below "Drawing" - e.g. "Clear"
4. Resize Game window
5. Observe Game Window flickering/drawn scene disappearing

Expected: When selecting "Clear" in Frame debugger, the scene becomes black, resize has no effects
Actual: When selecting "Clear" in Frame debugger, the scene is still visible, resizing causes it to go black/occasionally flicker

Reproduced on: 5.6.0b4 (Metal, OpenGL)
Did not reproduce on: 5.5.0p3, 5.4.4f1

Note: only reproduced flickering on OpenGL, not Metal API, however doesn't seem to be as severe as in screenshots. The errors in console are also not there in either Graphics API.