No Ambient.cave sounds playing while inside both Single and Multiplayer/Realms worlds

Hello, I've noticed that ever since 1.9 itself launched, I haven't heard any form of ambient noise playing (for the caves). They are in the game and work just fine however, because I can get them if I enter the /playsound command into the bar (/playsound ambient.cave ambient [player]). I just don't ever hear them play naturally in environments.

The Ambience slider is turned all the way up to 100%, as is the sound volume. If I turn on the subtitles it will say "eerie noise," but there are none playing.

I am currently running on Windows 8 through the 1.6.61 launcher, using version 1.9.4