Yea its kinda buggy so use it wisely, but you can try and work around it, i made the experience if you turn the Trainer off with toggling f1 again or close it. It should fix the problem in the most cases if it doesn't help at all you have to restart the witcher 3, dont worry that you lose much progress, if the infinite loading is in a Cutscene, you start right after the Cutscene and if it's after killing some stuff or teleported somewhere you should end where you was before getting the infinite loading