I'd say that there are variations on the UCD list, same as you. One guy on here says he has 9 2Js, that they come up frequently, etc. I'm the same as you. I have one and only one has ever come up. I check the UCD after every few races, the ones at the bottom are not 'justin' so I know I'm not missing it. Additionally, I've checked when the next one is due, turns out it's 1100 days. Given that some people have multiples of it, and the next one for me is 1100 days away, I can't see how the lists are the same for each player. I'm not frantic to get another, just pointing out the variation.
Edit: Just checked again and it's 1403 days. Maybe my 1100 was wrong since it wasn't that long ago that I checked. (TTs don't change the UCD list, only races and license tests. Most of you know that, just pointing it out for the new peeps.)
What would help here is if one of the folks who has lots would do the search thing after one comes up to see how many days till the next one. I've been online every day since May, to keep the 200%, and I haven't seen one twice. It would be nice to prove that the master list has variations. Tell you what, I get every frickin' Miata that's ever been made or ever been thought of!