I want to make an aquarium with kelp/seagrass. But when I try to place it in manually-placed water, the kelp/seagrass isn't waterlogged, breaking the kelp/seagrass. Oddly enough, you can only place ONE kelp with commands in this situation. If you try to place another directly on top, it will break both. I can't provide any visual evidence because I have no screen recorder. This does not affect Sea Pickles nor does it happen in naturally generated water.
Sea plants, coral, and pickles can only be placed in water source blocks, not flowing water