When I queue an at job consisting of nothing but a one-line echo command "echo foo", here's what the resulting file in /var/spool/at looks like:

${SHELL:-/bin/sh} << `(dd if=/dev/urandom count=200 bs=1 2>/dev/null|LC_ALL=C tr -d -c '[:alnum:]')`

echo foo

I don't know where that garbage after the << is coming from, but it's clearly completely borked, and when the at job runs, I see this:

sh: line 63: warning: here-document at line 60 delimited by end-of-file (wanted ``(dd if=/dev/urandom count=200 bs=1 2>/dev/null|LC_ALL=C tr -d -c [:alnum:])`')

I'm current from rawhide, including at-3.1.10-27.fc11.i386.