When you harvest sweet berries by right clicking them they drop on the ground as if you have mined them. To my knowledge they should go directly into your inventory when harvesting by right clicking simelar to taking items from a flower pot and like on Minecraft Playstation 4 Edition.

Note: The expected behavior was present before 1.12. Before 1.12 they went directly to my inventory as expected but for some reason they also drop as an item in this version now.