Steps to reproduce:

• /gamemode creative
• Get a decorated pot
• /gamemode survival
• Put the decorated pot item in your offhand slot
• Now, place the decorated pot down
• The decorated pot abruptly disappears from your hand and is placed down, without any animation
• Notice how there's no placing animation playing like there would be if you placed the decorated pot with your main hand?

This only works if the player is in survival mode and tries to place a decorated pot from their offhand.
Creative mode works as expected when placing a decorated pot from the offhand - it plays an animation.