Water source block not updating after waterlogged block was removed from its place:

I was making, or trying to make the smallest prison ever, and i had a waterlogged stair that was facing a cauldron that the player would get into and i would close a trap door over them, and if u broke the cauldron, water would flow in and lava would dispense so you would soffocate in obsidian. i had copper trapdoors on either side of the waterlogged stair. the stair had no blocks beneith it, and 3 on its side. ive done this around 3 times, and the water wont flow, as if its still waterlogged in a stair. if you update the black afterwards, that fixes it. i unfortunatly dont have screenshots as im on my pc rn.