We never fixed it and there is no know fix to the issue until now. My team looked everywhere and only found that for FMOD the audio gets synchronization problems in the web build. If you use the app everything will be perfect. I thought it was only an FMOD problem so I thought about switching to WWISE or another engine, but playing your game and communicating with you have shown me that it is something that will happen with web builds regardless of the engine.