Bluetooth headset delay To start off I am not really sure if this is hardware (headphones or the phone) or android specific issue/feature. Maybe there is an android workaround for the hardware feature hence this kind of fits here the best.

Google is full of similar topics, but all I've seen are related to windows and not really this kind of delay.

Up until recently I've been using wired headphones, but I started using bluetooth ones and I hit this weird delay when using an app like Duolingo.
When there is no sound for a few seconds playing there is a slight delay when the sound is actually played.
Let's say I do 5 exercises in a row and I do it very quick- no issue.
Then I come to a more complex one that I need more time to do, the sound that plays after submitting an answer is slightly delayed.

When listening to music there are no issues, which would point me to believe that the headset is actually going to some sort of sleep mode when there is no audio played from the source device.

Sony Xperia M2 android 5.1.1

Headphones are Marshall Major II wireless

Do you know of a way to fix/counter-act this annoying bug/feature?
Did you use custom sound app? like viper or something?
I suspect those app are the thing that cause the problem.

Try to use on another device (android devices).
If there are no problems there then I could assume the problem between software or hardware on your android device.

Hope that helps.