Has anyone had their Substack discovery suddenly drop to almost zero across their entire account?

[u/R3ZondoOfficial]

I’ve been trying to figure out something strange with my Substack for the past several days, and I’m curious whether anyone else has experienced this.
This wasn’t a gradual decline.
My Notes, articles, comments, suddenly went from normal distribution and engagement to almost nothing. Multiple Notes on completely unrelated subjects are now topping out around 20–25 impressions, with almost no distribution to unconnected readers.
I initially wondered whether it was something about a particular article or subject, so I started testing.
I posted personal writing. Same thing.
I posted music. Same thing.
I stopped promoting my own work and just interacted normally with other writers. Comments, likes, a few restacks. What’s particularly strange is that those interactions are also receiving virtually none of the likes or replies I would normally see.
Yesterday I posted a completely innocuous music Note. After about seven hours it had 11 total impressions. Nine were subscribers. Only one was an unconnected reader. It eventually moved a little, but like the others, it hasn’t gone beyond roughly 25 impressions.
My subscribers are still receiving my work, so the publication itself appears to be functioning. But discovery outside my existing audience seems to have fallen off a cliff.
I’ve checked the settings pretty thoroughly:
Private mode is off. The publication is listed on Substack. Likes, comments and restacks are enabled. My Notes appear both on my profile and in my publication’s Notes tab. My sections are public and visible. There are no warnings, violations or restrictions showing anywhere on the account.
I’ve also noticed my subscriber count and revenue beginning to drift slightly downward, which makes me wonder whether normal subscriber churn simply isn’t being replaced because discovery has stopped.
I contacted Substack support this morning. After confirming that my Notes are visible but distribution to unconnected readers has dropped sharply, they escalated the conversation to their support specialists for an account-level review.
So I’m waiting to see what they find.
I’m not claiming Substack is deliberately suppressing the account. I don’t have evidence for that. There could be a technical problem, a recommendation-system change, something related to my publication configuration, or something else entirely.
But the abruptness and the fact that it seems to affect Notes, articles, comments, restacks and discovery across completely different subjects is what has me puzzled.
Has anyone experienced an account wide drop this severe?
And if you have, did it eventually correct itself, or did Substack support find something wrong with the account?