Reduced Distribution of Viva Engage Weekly "Discovery" Digest Email

I'm interested in knowing if others have seen changes in the distribution of the Viva Engage Weekly "Discovery" Digest Email.  We are on the standard M365 A5 for Faculty plan, and always experienced a high level of user engagement following the email digest going out.  This had reduced significantly over the last 8 weeks.

This week only ~1500 digest emails with the subject line "Discover what’s happening across your organization" were sent.  We used to see ~6500!

I suspect a change in the Algorithm.  This Blog post describes the fundamentals: Viva Engage Explained: Email Digests - Microsoft Community Hub

Do we expect everyone to receive a Discovery Digest (if they have it selected in their Notifications)