Rain leaking when there block is located in y 255

From past, when there are blocks in y255, regardless how many blocks are located under that block, the rain goes threw the blocks. It is limited to exact coordinate where blocks are located in y255. So when you build skyscrapers touching y255, that building will have water leak. Please fix this. This was a long term issue and as I'm continuing to build high rised building more and more, it stress me out.  Thank you.