Hopefully a member of the development team sees this.
As a fellow web developer, I understand that big changes to a production site can have some unintended consequences so I wish you the best in fixing these issues.
Please let me know if I can help in any way.
Update 1 [2017/04/27 08:11]: I have contacted the Duolingo team with a bug report.
You can report a bug directly via this link:
Awesome! I was low on time this morning and didn't want to search around for a bug report link. Thanks.
I've file a bug report with the Duolingo team. I'll try to keep this thread updated if I hear anything.
The "r" issue appears to be only in Firefox on Linux. I'll verify it's still an issue when later today. IE11 appears to be working fine now. Maybe something was cached or your team fixed it with a patch. Either way great work. Love the site and response for an actual developer!
[Update] "r" on Firefox version of Linux is all good.