As depicted below, the logo appears to have a rather odd white shape on the left of the 'Raspberry', which doesn't fit with the logo's border.
This change only recently occurred in the last couple of days, and the meta logo appears unaffected. I've not observed any logo glitching on other sites either, so I'm assuming only this site is affected so far.
I've observed this behaviour in both Chrome 65 and Firefox 59 - the logo appears in the exact same way as the above image in both browsers.
Possibly related: Cryptography's logo is also broken with a similar issue.