Samsung A5 2016 Battery empty at 30%

So my a5 his battery goes from 100 to 30 and at 30 percent it just shuts down. 1/100 times it goes to 5%. Its really weird.

I sent my phone to a repaircenter and they replaced the battery but I still got the same issue.

Is this something common? Does this fall under the warranty of samsung?

That normally indicates a bad battery. Batteries are warrantied for six months I believe.

Perhaps there is another hardware problem, or a software one.