We were having this issue as well, in 2016. NAMECASE GENERAL NO had no effect. I didn't read Paul's comment carefully, but he is correct. Adding
<!--Arbortext, Inc., 1988-2015, v.4002-->
To the top of our SGML file solved the problem.
Never noticed a problem, and we have numerous U/LC attributes. But all of our document have
<!--Arbortext, Inc., 1988-2016, v.4002-->
at the top and it all works well. The only thing is a generated ID, if its SGML it lowercases it, if you are XML it keeps it as typed
even if its a generated CamelCase id.