One item carried by the UK’s Daily Express this month was a negative on the mushroom PR front.
The article on the paper’s website was on the subject of bloating, and identified mushrooms as being one of the vegetables likely to cause it. The reason it seems is that mushrooms contain the sugar raffinose.
Of course loads of vegetable contain raffinose - the trisaccharide composed of galactose, glucose, and fructose - it can be found in beans, cabbage, brussels sprouts, broccoli, asparagus, other vegetables, and whole grains. So perhaps the mushrooms were being unfairly singled out.