Well, when we found out that Sharon Stone is also in The Laundromat, someone on Awards Watch pointed out that the project Sharon Stone was talking about with Meryl was most likely The Laundromat, while the project with Scorsese was a Bob Dylan documentary, which came out this summer.
Here's is the original quote:
Stone began by talking about her latest project, a create-your-own-murder-mystery called Mosaic with Steven Soderbergh, as well as her new secret Netflix project with Meryl Streep and Martin Scorsese. Literally, it's so secret all we know is that it's a docu-drama that's not about Stone, but not not about Stone, as she's a character. "I'm gonna blow it if I keep talking. It is about one of my favorite people, and someone who is one of your favorite people, so it's gonna be good." I have a lot of favorite people, Sharon! Give me a hint or two.
After reading this again, and knowing that Stone was indeed involved in the Dylan project with Scorsese, it seems so obvious that it was just a reporting error, and no such project with Streep, Stone, and Scorsese was or is planned.
Not that we'd be against there being one in the future, however.