Expected behavior: the "indoors" rain sound should play when in houses with glass windows.
Observed behavior: the game acts like glass windows are empty holes and plays the "outdoors" rain sound even if the player is indoors.
To reproduce: build a house with many glass walls in a biome that supports rain, then use /toggledownfall to start rain.
Unable to reproduce, rain muffles as soon as I move away from walls, regardless of whether solid or glass.