Beds have a block-entity which is used as a hack to store the "color" property due to it not fitting in the NBT. However, bed items don't use this, they use the data value of the item. Therefore they do not and should not copy blockentity NBT when middle-clicked.

TL;DR:
Expected: ctrl+ block-picking a bed should give a bed item with no extradata.
Actual: Bed block-picked item has a (+DATA) field on it.