After this, I was able to continue the scene by hitting "Ignore", and it looked totally normal. Then the Cordelia friendship date immediately started, and also looked fine at first, but after reaching the sunset, Cordelia's sprite seems to stay stuck on the serious-ish open-mouth sprite. There's no sprite change anymore, including at parts where I'm fairly sure she was smiling when I got this scene in other runs.
I'm able to scroll back through the script and the last other sprite is her smiling sprite at "... was he wrong? / Not in my case at least." After that, the background changes to the sunset and the open-mouth sprite stays on.
There's no other problem, the night sky background loads fine (but then open-mouth Cordelia comes back) and I can end the scene just fine.