Well, I didn't notice the change first time as well :joy: I've had a similar problem with a change in sims' appearance before - not just the portrait panel but their actual look as well.
The change itself was kind of random but it's usually mild (and harmless to normal gameplay). There was a time when I noticed that a male sim of mine (who I've made using custom facial sliders) had a longer, sharper chin with his cheek bones moving a little bit upwards than the time I created him. I didn't figure out another way to fix it other than editing it directly in CAS though. @Mikezumi do you have any custom CAS facial sliders installed?