I saw this earlier, and I'm not sure who on the team has any real form of relationship with Betty. Sam sure as hell doesn't give her the time of day, and it doesn't seem that she really interacts with any of them.
Jet hasn't posted on X in a little while, but that's not confirmation in the slightest, he might be taking a break?
While I'm happy to accept that it is a possibility I can't imagine the person who would know for sure early on would be Betty.
However it should be noted that Jet last posted three days ago, so maybe that shit happened sometime in the last 72 hours(?), so it's possible she heard something.