Thank you for the follow up (let me know if I should use some other bug reporting mechanism).
It first started maybe a week ago. It seems all the reviews are pretty slow. I also noticed lessons slowing down–at first they were perfectly fast but in the last session it slowed down as I moved farther on. In contrast all the reviews are equally slow from the beginning.
I periodically restart computer and browser. I’ll pay attention to whether this is related more carefully in the next review sessions. I’d be happy to try any troubleshooting techniques, diagnostics, or applications you recommend.
Also when using my other computer at home (Windows 7, chrome) there is no noticeable delay at all.