Rain renders through blocks that don't have anything but sky behind them (with exceptions).

• Very inconsistent, rain that renders through is shown for about a second, then it's normal, then you can see it again. "Flashes" seem to come in small groups.
• All blocks that had rain had nothing but sky behind, apart from the quartz stairs in the third image, which is where I first noticed it.
• some blocks only rendered rain from certain angles, might be because there is something to the side of them that would block the rain if the block wasn't there.
• The screenshots only have it render through non-full blocks, but one time it did render through an acacia log, which is definitely solid. This one had empty sky behind it.
• Appears to stop occurring at nighttime
• Some other exceptions to the empty sky rule in the 2nd screenshot.
• The world has enough redstone in it to strain my FPS (PC is average to bad) but I'm pretty sure this wouldn't cause rendering glitches.
• Under an hour of gameplay since updating to 1.15

Hope this helps!