Here's a picture of an Emerald plant that has four of the large flower clusters forced by fall pruning. These berries, in my greenhouse, will be several months earlier maturity than normal. Last winter I had some great fruit like this off Santa Fe. The berries ripened in Jan/Febr, were large and much more tart than normal due to cool temps but very tasty as that variety usually has no tartness. Star had similar clusters of berries 2-3 times as big as normal.

Picture taken today.

Fall pruning can also force normal clusters of normal size berries. I'm going to have a little fruit ripening all winter and spring.

So I don't get it...don't they need a rest period/cold period? evergreen?

The place I've heard of a commercial crop in fall is southern CA. I think they force that crop by pruning as well. The one pictured in a small pot could be chilled at 40F for two weeks in a cold room and be ready to really bloom early. I think chilling would be effective in August in my conditions. But you'd need a warm greenhouse in winter to make it work. Maybe 3 crops in 2 yrs. Don't think you could make 2 crops per yr without a lot of effort and money. But several sets on different 8 month cycles would give yr around fruit.