Water does not flow into these blocks independently, but if the water is poured into them using a bucket of water, there will be water in them. When to remove water from there with a bucket, the water will not flow there. (screenshot 1.4). Bug with a conduit is simpler, but also strange: initially, the water flows into this block, if you take the water from the bucket from there, it will not flow in there any more (screenshot 2.3).

    — Translated from Russian to English