I use pattern_router by default and have my translations split in couple of files for different components. But when I remove a component remove-unused always leaves some translations in the file and never removes it or leaves it empty. These leftovers are then reported as unused, but still can't be removed automatically as it should remove the file, but it doesn't. Another problem that may be related is when you have file that has no mapping in write section and all its translations are unused, remove-unused will leave it intact.