I completed the Personal Story that gave a Letter of Commendation as a reward. When I used it no Influence was added to my guild but I did get an update for the Active Guild Member achievement. Due to the achievement updating I assumed it was just the guild system lagging behind but it’s been at least a day or two now and still no sign of that 400 Influence in the guild history.
The 400 Influence doesn’t really matter since we only really need Influence for the Treasure Trove but that item was pretty much the only nice thing that came out of the whole Personal Story experience and then the game had to take that away too.