In 1.12 Snapshots 17w14a and 17w15a, Colored beds were added. The issue is, the default red beds before colored beds were added turns invisible when you play in your map or re-logging. The red beds that are existing in your world before the colored ones were added turns invisible when you reload the chunks where they are placed! The only way to make them visible again is by replacing them or staring at them in spectator mode!