So I was browsing the other Mazda3 forums and came across a thread about rust found between the trunk liner and the rear window. Looks like there are quite a few people who are having the same problems so I went outside to take a look at my car and there it is... rust forming on my 8 months old car... Seems to be an issue for the sedans only. I'd recommend Gen3 owners go and check their cars. I already called the dealer and bringing it in later in the afternoon. Took some quick pics at work but the quality isn't the best as it was sunny out and couldn't tell if they were good or not until I went back in.