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'Fate/Grand Order: Fujimaru Ritsuka wa Wakaranai' Anime Shorts Premiere on TV on July 2
(www.animenewsnetwork.com)
Considering how ridiculous a few of the incarnons get, letting them keep their high riven disposition is probably more than they're willing to let go.
Also I think that statement was originally more directed at balancing around SP enemies.
Looks like it's just the already existing episodes. They're running 5 episodes on the 2nd (i'm assuming it'll be the first 5). From the article's wording it'll either be just those five, or they might be airing a bundle of 5 every week until they run out.
If they keep the pace up it'll finish with 30 episodes (last one releasing at the 8th anniversary) so they'd have 6 weeks worth if they want to air them all.