As of this commit in baselayout: https://gitweb.gentoo.org/proj/baselayout.git/commit/?id=9cac4dd130637fa2c1f1a64bf3c9d2509284e6dd /etc/profile no longer processes ROOTPATH, and /etc/env.d/50baselayout no longer sets it. However, many other packages install files in /etc/env.d that do still set ROOTPATH. The result is that a ROOTPATH variable ends up polluting all users' shell environments. Suggest reinstating the "unset ROOTPATH" line in /etc/profile until all packages have dropped their ROOTPATH definitions in /etc/env.d.
By the way, while you're editing /etc/profile anyway, you should fix a typo: -# process *.sh files in /etc/profiled.d +# process *.sh files in /etc/profile.d
This is done in baselayout 2.6.