I wouldn't say it's a literal bug but maybe they were talking about this:

https://blog.chriszacharias.com/a-conspiracy-to-kill-ie6

This is incredible! I didn’t know the story! Thank you so much for finding the link, it’s a great piece of history!

Just a reminder, at that time you couldn’t do console.log(), because it worked with the devtools open, but “console” would be null with the devtools closed, which is treacherous because it only bugged for non-dev users. As a bonus, IE would ask the user whether they wanted to debug.