The Piglin Head block cannot be waterlogged in Java Edition. This is not the case in Bedrock Edition, and the Piglin Head was introduced after 1.15, making this a valid parity issue.

(It's worth noting that other head blocks have the same issue, but were introduced prior to 1.15 and are thus invalid...)

Steps to reproduce:

1. Place down a Piglin Head block in Java Edition
2. Attempt to waterlog it by placing a Water Bucket on it
3. Notice it does not get waterlogged in Java Edition
4. Repeat Steps 1-2 in Bedrock Edition
5. Notice it does get waterlogged in Bedrock Edition