I used to be in the small beer business and I can tell you that 95% of the time a microbrewery randomly has a raspberry or strawberry or blueberry ot whatever offering its almost without fail a beer that has gone "off" when fermenting. A beer being "off" won't make you sick or anything, but it does impart a harsh flavor, many times it will be bacto infection that hints towards vinegar. Smaller breweries don't want to toss whole cycles (shortsighted, I know), so instead they dump massive amounts of fruit flavorings to cover it up. Or turn it into a "shandy"
I implore you all to stop purchasing any seasonal shandys or fruit beers that they don't regularly advertise. The whole thing is a bruise on the industry.
Edit: Some people are interpreting this to say that fruit beers are bad, or are all repurposed. The point is just buyer beware, it's an incredibly common way to save batches that don't taste right.
And yeah... most small brewers despise brett and adjacent bacterias, with a passion... it's just stupid invasive in any system that isn't all metal and glass, and even then still can somehow find it's way.