LTW achieved but no perma plat status

[Vesca]

Two of my sim parents had an LTW of graduating 3 of their children from college, which I completed this morning - but they did not achieve the perma plat status   I worked my bahoovies off to graduate these kids (specially since I find Uni kind of boring) - is this some kind of bug?

[Ancient Sim]

Yes, it's a bug.  They have to actually be present on the campus lot when the third child comes back from their final exam or it doesn't register.  The same thing happens with several LTW's.  I had a Popularity Sim get her 20 Best Friends at a wedding and although the box came up, she never got the memory or the permanent platinum.