None of that happens for me, I would check out your ~/.login and ~/.tcsrc. Things to consider:
Are you starting tcsh as `tcsh -l` ?
'su' to root keeps you in /bin/tcsh ?
Does this happen when executing a script ?
Are commands you do not want to run except when logging in bracketed by
if ($?prompt) then
I noticed a very minor issue with /etc/csh.login, this line:
set path = ( $path /usr/games )
can cause duplicate entries to show up in $path, depending upon what you are doing. I changed it to
set path = ( /usr/local/bin /bin /usr/games )
in order to correct the issue. At one time in a prior release /etc/csh.login was changed to prevent dups, I think the change was different than above. I am planning to search for that change but been lazy so far