While I can't post an exact version when it started, the BGM from this game is now severely messed up in recent builds of the Android Version. The sound seems fine on the Windows version (tested with both the Android and Win64 versions of the v0.8.1-1076-g7a00891 revision). However, the sound effects seem fine.
EDIT: Poking around on the forums, I saw the recent issues with ARMJIT on android. It seems the issue may be related to that, because on the revision that gets recommended in the meantime until they fix it (v0.8.1-1029-g51596b6) has perfect audio.
EDIT: Poking around on the forums, I saw the recent issues with ARMJIT on android. It seems the issue may be related to that, because on the revision that gets recommended in the meantime until they fix it (v0.8.1-1029-g51596b6) has perfect audio.

