left speaker at the bottom of the phone doesn’t work

I just bought a new xr a few weeks ago and as I was using it I started to notice that one of the two speakers (specifically the left one) at the bottom of the phone doesn’t work or isn’t as loud as the other when I use my finger to cover and muffle the sound of the right speaker. Is this just some software bug or is the speaker really isn’t working? Does anyone of you notice the same thing? If not please try what I did. Thanks in advance.