May I suggest a small addition to the user manual?
This is certainly useless for experimented users, but I think it may avoid unnecessary debugging time to beginners.
In Section 12.1.12 Comparing for Inequality, the following should be added:
WARNING: "neq..." is nor equivalent to "(not (eq ..."
Example:
(neq 3 3 4) = FALSE
(not (eq 3 3 4)) = TRUE
And similar addition to section 12.1.14 for <>