The promo anime was always slightly erratic, roughly following a monthly schedule but sometimes adjusting that so there would be an episode at the very beginning and very end of a single month, and then picking back up again monthly two months later, sometimes focusing some of those episodes around a specific in-person event or anniversary live stream.
... which is all to say, no, it's never had a very strict schedule.
As a reminder, we do have an actual full website (!!!), and we do have a complete list of episodes and their debut dates:
https://www.kanzenshuu.com/episode/sdbh-promo/list/
The official website for the series does not currently list any info about a third episode of the current arc:
https://www.carddass.com/dbh/sdbh_ugm/anime/
... but it's been about two months since the last episode, and in recent memory they've had some fairly quick turnaround times between announcement and release.
It's worth pointing out that this is a region-restricted online-only series intended strictly for a Japanese audience, so while I don't necessarily see much of it here exactly, it's always good to remember that unless that's you (someone physically Japan who also speaks Japanese), this series isn't "for you" and there's not much worth getting up in arms about over its schedule or content.
:: [| Mike "VegettoEX" LaBrie |] ::
:: [|
Kanzenshuu - Co-Founder/Administrator, Podcast Host, News Manager
(note: our "job" titles are arbitrary and meaningless) |] ::
:: [| Website: January 1998 |] :: [| Podcast: November 2005 |] :: [| Fusion: April 2012 |] :: [| Wiki: 20XX |] ::