It's not cargo-cult: anyone who's worked on cross-browser front-end development probably encountered this at least once. I ran into this personally a few years back when I was trying to be too clever by half with base64-encoded queries. It's not just ancient IE that has limits - in my case it was a corporate proxy that was truncating the query (which is why only that customer was getting that bug). A year or 2 before that, I ran into the MSIE limit (must have been IE8 or 9: don't know if that counts as the Triassic period, because I don't know what we'd call the IE4-6 era)

I did encounter this multiple times...not in the last decade though.