Several blocks that are not containers can have items replaced and some blocks can have items replaced in slots that are only meant for specific items.

Cauldrons are not containers and yet they have 10 slots according to the replaceitem command. Attached is an image of a cauldron +data, it contains 10 stacks of bread. They are not dropped when the cauldron is broken.

It is also possible to replaceitem on the beacons, which are no more a container than a crafting table is. The same goes for all the chemistry blocks when education edition is on.

You can also replace items in slots where they are not meant to go. For example: You can replace bread in a jukebox. You can replace bread in a lectern and it will appear as an empty book; if punched to remove, it will drop as bread. Additionally, you can replaceitems in fuel slots of furnaces and brewing stands, despite said items not actually being fuel.

This is also an issue on latest version of BDS.