If you overcharge the brake pipe to get a faster release throughout the consist and then go back to the normal release or the neutral position the brake cylinder gets charged. Even, thou the brake pipe stays at its 5-bar standard pressure. Meaning that the brake becomes stuck on at the loco and there is no way to fix this. The only thing one can do is to restart the entire scenario/service. This only happens when you have waggons attached to the loco. If decouple the brakes can be released by overcharging them again. Afterwards they stay released like they should, but once you couple back up to the waggons the become stuck on again like before.