Hey Chet, I can reproduce it. What can I do to help tracking it down?
bon...@core:~/devel/bash-4.0$ ./bash -c 'echo $(echo \|)' ./bash: command substitution: line 1: syntax error near unexpected token `)' ./bash: command substitution: line 1: `echo \|)' bon...@core:~/devel/bash-4.0$ ./bash -c 'echo $BASH_VERSION' 4.0.33(1)-release Jan aka TheBonsai