gnufind implicit "-and" operator

[tim . largy]

The gnufind man page states that expressions are composed of options,
tests, and actions, all separated by operators, and that "-and is
assumed where the operator is omitted." Therefore I don't understand
why:

        find . -operator -print

works, but

        find . -operator -and -print

doesn't work for many operators (resulting in error message "invalid
expression"). According to my reading of the man page they should be
identical. To be more specific, the following do not work:

        find . -mindepth 1 -and -print
        find . -maxdepth 1 -and -print
        find . -mount -and -print
        find . -noleaf -and -print
        find . -xdepth -and -print

however the following do work:

        find . -help -and -print
        find . -version -and -print

presumably because -help and -version short-circuit the parsing logic.
Have I run into a bug or am I misunderstanding the gnufind expression
syntax?

Tim