It's raining...inside???

This never happened in the previous snapshots that I have played before. When it started raining, I went inside my house that I've built in Creative Mode only to find out that it was raining inside. (This is the same for the pig's house and the horses' stable) I don't what could be the case as I have recently started playing Minecraft: Java Edition recently (March 2020).  

Below are screenshots of the issue that I have.