Flowing water creates sources in slabs

The bug

When you place a slab directly into flowing water, it creates a new water source in the block, regardless of the hight of the flowing water. Also, the created water can fill a bucket but will be replenished before disappearing. In the attached image, the only source placed with a bucket is the one on the lime concrete. Applies to both top and bottom half slabs of all types.

How to reproduce

1. Place a water source that creates flowing water.
2. Place a slab in the water, it will turn into a waterlogged source block.