When using fast-forward with the Vulkan renderer, the screen flickers to black for a moment when turning it on or off. It doesn’t seem to matter what core is running, the result is the same. You can workaround it by just tapping ‘f’ twice to go into windowed and back to fullscreen, but you have to do this every time Retroarch is booted up. It looks like it might be a Vulkan-only (and nVidia only) thing, a google search showed some other people mentioning it a few years ago and that it got fixed.
Anyone else seen this and knows if there’s a simple setting or fix for it?