You can place fire with flint and steel or fire charge on waterlogged blocks, which doesn't make sense as the waterlogged blocks contain the water block.

How to Reproduce
1. Place any waterlogged blocks such as leaves or fences in the water.
2. Try to place the fire on top of it.

Observed Result
You can place the fire on top of the waterlogged blocks, but the fire disappears quickly, causing the item to be used up.

Expected Result
You're unable to place fire at all on waterlogged blocks.