What world and location is this at?
Yes, it seems that the items placed on the Shop Stand are positioned differently compared to if you just placed them on top like a normal block. A bug has been logged.
Were you stuck in the ground perhaps? Go into the third person if this happens again. If it turns that you were stuck in the ground, then we should hopefully have a fix for them in the next update.
So you originally had the Fibrous / Inky in your Inventory, but after making space, you then find yourself unable to pick it up again? We've reproduced it like this, so a bug has been logged, unless your method differed slightly.
We've included this into the bug database.