OpenGL display driver: black screen when toggling fullscreen off

[0x07cf-dev]

For some background, I have had a portable install of mGBA 0.9.3 for a couple of years or so, no issues at all.
It was today, when I decided to install ES-DE to centralize all my emulators and games, that a peculiar issue arose.

I proceeded to simply copy my entire (working) mGBA portable install to ES-DE\Emulators\mGBA and I tried running the new copy of the emulator to test it out: it launched and loaded the rom properly, but it had been automatically set to fullscreen so I left-clicked twice to toggle it off... and suddenly everything went black (the emulator, not my whole display), with the sound still on.

So I started testing things out, looking for a cause and more symptoms. I noticed that this only happens when the display driver is set to OpenGL , but the video renderer can be freely set to OpenGL (in every case i tested). I tried switching it multiple times, and I can confirm that, as far as I've seen, this does not happen with Software or OpenGL (1.x). But this seemed strange to me, I had the feeling that I had always used OpenGL in my working install of mGBA, so I decided to launch it to check the settings and indeed, the display driver was set to OpenGL in the original copy, and the fullscreen toggling worked flawlessly with OpenGL. This is what perplexes me the most.

So, my original 0.9.3 install works as it should with display driver set to OpenGL: I can open the emulator, load a rom and spam left-click on the screen and fullscreen toggles on/off without a single problem (with x8 upscaling enhancement); all other portable installs of mGBA 0.9.3, in any other path, do not work with display driver set to OpenGL and will make my emulator black upon toggling fullscreen off (also looks blurry with Software display driver).

Once fullscreen has been toggled off and the emulator has gone fully black, not even Emulation > Reset will fix it, only re-opening the emulator and manually loading the rom makes OpenGL work properly as a display driver... until fullscreen is toggled off again. The rom I load does not matter either.

I have already taken a look at both #2781 and #1414 and searched through the issues, but I am yet to find anything useful to my particular case. I can get the OpenGL display driver to work in one specific instance, instead of none. This seems to always happen with any install of mGBA that isn't my original one, as I have already tried: copying it to a new path; copying its configuration on top of a fresh 0.9.3 install; testing with newer versions (0.10.3 and 0.11-8482). In all cases, the result was still the same.

I hope we can troubleshoot this together, and please do let me know if I need to follow-up with additional information.
Thank you immensely for your time and patience.

EDIT: further investigation shows that this depends on the path somehow. If i rename the directory the emulator is in, OpenGL stops working, and if I rename it back then it works again.

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• os: Windows 11 23H2
• cpu: AMD Ryzen 9 5900x
• gpu: AMD Radeon RX 6650xt