You can use blocks in your offhand slot if you have food in your main hand but your hunger bar is full

Not sure whether this is intended or not.

The bug

When you hold a block in your offhand slot, a food item in your main hand, and your hunger bar is full, you're able to place that block. As per MC-126337, this should not be possible. This is especially annoying if you just finished eating and you're looking at a block, so you accidentally place the block in your offhand.

To reproduce

1. Be in Survival mode
2. Get hungry
3. Put a block in your offhand slot
4. Eat something
5. Accidentally place 20 blocks