Game occasionally plays audio, despite Sound: Off in settings

[NYPup2Train]

As the title says, even though I have Sound set to "Off" in the Settings, occasionally the game will let out a short burst of sound, usually two or three notes of (what I've determined to be, by temporarily enabling it) the background music that plays when Sound is set to "On". It only ever lasts a second or so, and then cuts off again.

Best I can tell, it seems this occurs when the page has been sitting idle for a while, and then some event fires or timer expires that triggers  a burst of new activity in the interface. So, here's my conjecture (purely theoretical) for a possible sequence of events. Most likely there's some flaw in my assumptions or reasoning that would rule out this exact scenario, but perhaps it can point in the right direction to find the actual source of the problem:

1. The interface sits idle for some length of time (that appears to be a necessary precondition for this sound bug to occur)
2. Something occurs that triggers changes/updates to the interface, like automatically bringing up the (real-money) store dialog
3. Because the page had been idle for some time, the local copy of my user data has expired and needs to be refreshed from the server
4. Until that refresh completes, the fact that I have sound disabled in the Settings can't be determined.
5. The audio code really wants to play some music, and can't get an answer on whether or not I've disabled that pending the user data refresh
6. Too impatient to wait any longer, the audio code starts playback on the grounds that a check of my Sound setting value didn't come back with "off" (or anything else, so far), and if sound's not "off" it's allowed to play music.
7. The refresh/update of user data finally completes, and access to my settings values is restored
8. The audio code finally receives the "off" answer it needs, and begrudgingly halts playback.

OTOH, I may be talking nonsense. Perhaps none of the crap I dreamed up here is even a tiny bit correct or feasible. The real problem may have absolutely nothing to do with any of this. Definitely still happens, though, for whatever reason.

Forgot a critically important detail: This only seems to happen in Windows 10. I also use Linux, and haven't ever had the game "leak" sound there. (Google Chrome is the browser in both cases.)

Edited November 10, 2022 by NYPup2Train
Add OS info.