https://youtu.be/BQG03ultoow
I have a video of it occurring. It happened seemingly at random as I was commercing and didn't notice as I was often listening to my own music, or in a voice call at the time (not at the time of taking the video)
Observances:
My BGM suddenly got frightfully quiet despite my options not changing (its always low, but I can usually still HEAR it.)
Even maxing out the volume renders the BGM relatively quiet.
Simultaneously, several sound effects also became very quiet (such as opening inventory and skill windows) while others (such as footsteps and skills) remained audible.
Concerningly: Music started infinitely looping over itself and never stopping. Audible in the video is the Commerce Start Theme, the Commerce Battle Theme, Osna Sail's theme, Hyacinth in Lips, and Dunbarton's theme all playing simultaneously at very low volume.
I am unsure what the trigger is, but my gameplay as of the day was:
I open the window to the game after having it minimized overnight. I begin to commerce. I do not recognise anything amiss however I am listening to my own music, so I am unsure if the issue had already occured or not. I continue to commerce. I do not at any point summon any dollbags or travel by boat and I do not enter any buildings. I do summon my William Pet.
I notice pulse of purification ambiently pulses in every map however I think that's unrelated and part of a different bug. I don't think Pulse of Purification affects ambient sound nearby me.
Relogging does not fix the game. (The pulse also persists if i relog near it while I'm on the character select screen. I don't think its related. but you never know.)
I restart the client (I do not repair install or anything.)
I don't recognise the log-in music - perhaps the issue began when I opened the client yesterday and I didn't notice.
-# What is this log-in music...?
Relogging has solved the issue.