I've been participating in SE for a while -- particularly in beta sites. I have an account on three and I checked my account page today. I did a double take upon seeing no distinguishing white letter on any of the favicon's for the beta sites as there always have been. Were they recently removed or did I just find the bug of the day?
It's also missing from the Stack Exchange Dropdown:
All the icons link to a single icon rather than site-specific icons: