Just like Leviathan had "Jump torpedoes" that had to be explicitly nixxed subsequently. Sometimes stuff slips past the editors.
In LBB1 77 it was a jump capable 50kg missile.
I still sort of like the idea of "sub-volume" jump devices like jump torpedoes. I believe TNE used ~ 50ton "Jump-Boats" in the Regency as part of its "X-Web" system, and simply noted that they had a significant risk of mis-jump and suffered high loss rates. That might be the simplest (and a believable) solution to the issue.