Drag and drop tutorial issue

I’ve been watching the stream to get a drag and drop inventory system working but I’ve come across a issue that I only seem to be having from what I’ve searched.

My issue is when I drag and drop a item onto my action bar it drops it completely instead. If I take the functionality away of dropping an item it works fine.

Here’s the blueprint for mine

[Here’s the timecode for the stream][2]

Is someone about that’s done this tutorial and could lend a hand?