Secret of Cabot House artifact reward unobtainable if Jack becomes old Jack

[Warrior 7]

It seems that the Unofficial Patch fix that repaired Jack Cabot and his family changing to their "aged" appearances also unintentionally unmasked another bug. After the completion of Secret of Cabot House, if you side with Jack and kill Lorenzo at Parsons, he will ask you to come back in a week to get the Lorenzo's Artifact Gun. After a week, the objective to "Talk to Jack about the artifact" is added to the misc section of your journal, and points to Jack himself. Unfortunately, if you delay going to Parsons to talk to him long enough, say, because you're in survival mode and no fast travel makes getting up there painful, then he reverts to his aged appearance, and the quest can no longer be completed; the "aged" Jack will not talk to you about the artifact, and the quest marker points to a spot in space where I presume the young Jack Cabot is standing but disabled. This makes completing the quest and getting the gun impossible without the console (or a mod to re-enable it in survival).