When use unity Microphone.Start and pause fmod then resume after stop record

when use unity Microphone.Start to record audio and pause fmod then resume after stop record.
the problem is: the bgm sound will appear after a few seconds (7second or more). on ios phone.
why there is a delay?

begin record:
OnApplicationPause(true);
Microphone.Start(xxx)

end record:
Microphone.Stop()
OnApplicationPause(false);

OnApplicationPause will be calling coreSystem.mixerSuspend/Resume which will stop all sounds running in FMOD, although I’m not sure why there would be a delay in resuming.

If you don’t want the sounds to actually pause, you could also use RuntimeManager.MuteAllEvents.

It is my fault, i make a delay manually in the code, so the sound can not resumed immediately. thank u very much.