nothing new. but blizzard WANTS the community to be toxic and have meta and stuff.
in short you should be able to play any key you want at a difficulty you finished max, like with current keystones, i mean you played a +15 you finished ++ then you are able to play any key at 17, and then it quickly will cap you based on your skill level. there in nothing breaking to the game. the most important part you can retry the same key and improve, right now you can’t do it. blizzard just wastes your time and nerves.