Iphone 5s loud speaker problem - second replacement?!

Hello,

I've noticed that sometimes my loud speaker goes heavily distorted and sounds like 150% volume level while is set to 50%. It happens when typing on keyboard or watching movies etc. but it's not all the time. Usually it works good but I never know when it will be "super loud" , I had that problem couple times in public (quiet) places and it emberassed me when speaker suddenly goes distored and 150% of volume...

Here is a video of it, notice that Iphone has been factory restored so it's not software problem:

https://www.youtube.com/watch?v=M2Pwu2cLUhs

I assume that it will be replaced because of my valid warranty... It is my second Iphone that is broken and I have tempered glass installed on it which is not cheap, so will service include it while replacing? ...