The bug
You can't waterlog a decorated pot by using a water bucket or a dispenser, despite the fact that they can be waterlogged.
To reproduce
Place decorated pot
Use a water bucket on it
Observed result
The water will be placed beside or on top of the pot.
Attachments
Comments 4
Dispensers cannot waterlog them either. If you waterlog one using a debug stick, water does not flow out of its tile space, but it can still be used to create an infinite water source with another water source (2 waterlogged pots do not create an infinite water source since they do not flow).
They can be waterlogged, you just are unable to do it using a water bucket.