Linux apps, such as ps(1), expects stuff in /proc/fd/ to be symlinks. I'm not sure how to fix it, because I'm not sure how that part of linprocfs actually works - it _somehow_ redirects /proc/fd to /dev/fd/.
So, the way it works right now is that for current process - and that process only - linprocfs provides a symlink from /proc/self/fd to /dev/fd.
Making this work properly would require adding file descriptor knowledge to procfs itself; possibly to pseudofs.
The current behaviour breaks tty(1) and a recent screen(1).