The bug

When a dispenser dispenses a Bucket of Tadpole above or below a dimension, the dispenser dispenses the Bucket of Tadpole item, rather than a tadpole. All other bucketed mobs dispense the entity when being dispensed above or below a dimension.

How to reproduce

1. Enter the Nether
2. Run the command:

   /setblock ~ 255 ~ dispenser[facing=up]

3. Run the command:

   /tp @s ~ 256 ~

4. Place a Bucket of Axolotl in the dispenser, and activate the dispenser with a button
   An axolotl is spawned above the dispenser
5. Place a Bucket of Tadpole in the dispenser, and activate the dispenser with a button
   The Bucket of Tadpole item is dispensed, rather than the tadpole

Expected behavior

The tadpole would be spawned when activating the dispenser.

Actual behavior

The Bucket of Tadpole is dropped when activating the dispenser.