So what?
So the jurors were explicitly WARNED not to communicate their deliberations or conclusions BEFORE the verdict was announced.
Presumably, as initially reported, the person learned of the coming guilty verdict before the case had been given to the jury for deliberation. If that’s the case, and it’s true, it would be a problem.
So what? If true if proves the jury discussed the case outside of court against their instructions, so the jury is tainted and thus the result is tainted.
If a juror has been speaking to someone OUTSIDE the pool of jurors, they are subjecting themselves to being INFLUENCED by that outsider and perhaps CHANGING their verdict upon being polled by the judge during issuance of the verdict.
IMO, Judge Merchan was the one who sounded the alarm over Anderson's post because Merchan wants a RETRIAL so that HE CAN ORDER TRUMP TO BE IN HIS COURTROOM FOR ANOTHER 6 TO 8 WEEKS. This is a great way for the deep state to keep Trump on a leash without imprisoning him.