So I've never set the reduceDebuginfo gamerule to true. It used to display co-ordinates correctly and now it's like without any co-ords. It only shows you the chunk number. Even the spectator mode special Mob-Effects don't work. For example if you spectate the Enderman's vision, it is inverted. As of right now, you can't see the co-ords and vision of Enderman and Creepers.
Check in your Chat Settings if "Reduced Debug Info" is turned on.