There is a bug with the pick block that allows players in creative mode to receive items they probably aren't supposed to have. You can set down a daylight sensor, invert it, and then use pick block on the inverted daylight sensor to obtain a block called: tile.daylight_detector_inverted.name. There might be more blocks that do this, but so far its only the daylight sensor.

If any of this other information is useful:

• The inverted daylight sensor used to obtain tile.daylight_detector_inverted.name was in full daylight
• The player obtaining tile.daylight_detector_inverted.name was in creative mode
• The world being played in had a few custom created resource and behavior packs that did nothing more than add a few mobs to the game
• The issue occurred in single player and multiplayer
• The keybind used for pick block was "P"