This needs to be a bug report. It's not something the course admins can fix. Lots of people are experiencing it. See the main discussion area.
Shouldn't malbona also mean "not good" in english translation. The weather is not good.
no. "malbona" means the opposite of 'good'; in english, that word is 'bad'.
"la vetero estas malbona" is different from "le vetero ne estas bona" in the basically same way "the weather is bad" is different from "the weather is not good". Not an enormous difference in English, but it is there
This isn't a big problem or anything, but often for me such as in this problem, the audio will but off the end so it sounds like "La vetero estas malb-". I often need to replay it and the second time the audio plays the whole way through, so it's alright. It just gets a little but annoying sometimes. Another thing - i noticed many discussions on duo about whether or not "malbona" means "not good" but I'm pretty sure it means "bad". So if you wanted to say not good, would you say "ne bona"? Thanks!
I've reported the audio bug several times and get thanks but no results. ☹️
My suggestion - write back and tell them that you won't use Duolingo till they fix it.
Here's a YouTube course which my son and I made a few years ago with the specific purpose of having audio with the classic "10 lesson email course." I find that the 10 lesson course (by email with a free tutor) is much better for learning the basics than Duolingo is.