Huge Memory Leak - D3D9 "Copy Depth Buffer" big issues after ALT+TAB

I've installed Reshade 4.9.1 on Half-Life 2: Update (DX9), and if I ALT+TAB with "Copy Depth Buffer Before Clear Operations" option selected, I get a NASTY MEMORY LEAK... (i need it to get depth+normal info for qUINT MXAO).

How it happens on my end: If I ALT+TAB and leave the game in the background for 1s-ish, SSD (IO) usage instantly maxes out at 100%, and as long as the game's window is in the background, RAM usage ramps up insanely fast (takes about 6 seconds to fill 16GB up). What that also means is: If I Alt+tab quickly out and in, SSD IO will max out, but RAM usage will increase just a bit, not ramping up to max.

After ALT+TABbing, the only way i've found to get RAM to a lower usage, and to normalize SSD IO usage, is to uncheck the option or close the game.

I have tested with and without any effect/shader enabled, but it doesn't seem to matter. I have not tested without any shader installed.

System info:
CPU: Intel i5 10400f
RAM: Crucial 16GB 2666MHz CL14
GPU: AMD RX 570 (21.9.2)
SSD: KINGSTON A400 480GB
SO: Windows 10 21H2
Reshade Version: 4.1.9

Are you running the game in Full Screen Exclusive mode?
With my DX9 games (especially pre-windows 7 games), I get some strange behavior when I ALT+TAB (aka use the Windows desktop). I suspect that those games weren't really designed to run in a borderless window mode, which allows you to minimize the window, etc. Windows 10 has some full screen optimizations that cause some memory issues with older DX games.

This is also happening to me in Portal (DirectX9). After alt-tabbing it starts leaking memory after ~10 seconds. It also leaks memory if I switch to windowed mode and minimize the game. It only happens when "copy depth buffer before clear operations" is enabled.

Specs:
CPU: AMD Ryzen 5 3600
GPU: Geforce RTX 3070
RAM: Crucial 16GB DDR4/3000MHz
OS: Windows 10