[JMT1985]

Is it normal for Sky Atlantic to have only 1-mins long ad breaks in the middle of the show, at least at peak times?

It appears to be the only Sky entertainment channel to have 2 internal ad breaks per hour instead of three.

Sky Atlantic as a subscription only channel from Sky probably can rely on the subscription revenue for it's budget rather than ad revenue and so Sky Atlantic maybe are able to have fairly short ad breaks, this could be a possible answer - the other answer is that they couldn't sell much ad space for those particular programmes and just aired the ads they managed to sell