Hearing In-Game sounds on Lol Client

Alright so, I 've been playing league since the 5.14 patch and had no probelms with client till now since I updated league to the 5.20 patch.

Here is the problem: I am hearing in game sounds whenever I start-up the client (launch, lobby, etc.)

What in game sounds? -lux sounds when she stuns an enemy -velkoz sounds -lucian shooting out his blast -the sound of money when you kill a minion/monster jg -teleport to base -some other one I can't identify

And these sounds repeat in sequence for the past hour.

I muted the lol client on my volume mixer (sound settings on windows) for now, but I would like to be able to hear my friends whenever they join the lobby. I have been looking at previous forums, but no one was able to explain the situation in detail and were pure comments/questions that added to the confusion. I am not sure if anyone else is having this problem, but please help me. This is something I myself don't know how to fix.