I was doing some testing for my HUD in a singleplayer single event 10 minute race around brands hatch with the GT3s. Shortly after it started, I went back into the menus, but then when I clicked resume, the menu disappeared, yet the game was still paused. It does not seem like a crash as Alt+F4 opens up the "Do you want to quit?" window (screenshot attached), but that's really the only thing I was able to do which made the game respond (that and taking a screenshot using F12). Tried throttle, brakes, ESC, switch camera, and more - all had no response from the game. This is already the second time it happens to me, last time was also when testing the HUD, so maybe related? But since I'm only reading stuff from the shared memory API, I don't think it could cause anything like this (it's not like the WebHUD or something that is built into the game)
Any idea what could cause this?