I read it differently; but since there's no suggestion Watt disputes this, or that Mitnick is unreliable on this, I don't understand the greatgrandparent post implication this is somehow indicative of shoddy journalism.

It's background info confirmed by at least one and probably multiple sources, and journalists specifically don't want to or need to footnote their stories with multiple named sources like a research paper or legal brief.

The author does say neither sides' lawyers acknowledge it. That indicates to me there's some reason to dispue it. If Watt doesn't dispute it, why isn't he quoted as saying so?

If it's not shoddy journalism, then it's shoddy writing.

Sounds to me like Watt and his lawyers have neither confirmed nor denied it -- it hasn't come up in the case, and there'e no reason to go on record either way. Quite possibly, she asked Watt's team, and they said something like "I have no information on that" or "I can't comment on things not part of this case".