I said this on the bird site, but I will say it here too.
I got a warning about this alleged zero-day in Signal and sent it to a few friends yesterday.
I am not sorry that I did, even if it turns out to be nothing.
Signal is critical for some of the people I reached out to. I'd rather warn them, and make them aware than presume it was all FUD and sit silent.
Mock all you want, I'd do it again a thousand times over.