$(echo ': ;false') vs $(echo false)

[Tom Rodman]

< not saying this is a bug..>
Why does this happen?:

         > 09:25:45 Fri Apr  6    ~
         > 1002 39 cmke787 rodmant > $(echo ': ; false') ; echo $?
         0
         > 09:30:32 Fri Apr  6    ~
         > 1003 39 cmke787 rodmant > $(echo false) ; echo $?
         1

How can I detect that "false" ran in the first example above?

         > 09:30:48 Fri Apr  6    ~
         > 1004 39 cmke787 rodmant > uname -a ;echo $BASH_VERSION
         Linux cmke787 2.2.14-5.0 #1 Tue Mar 7 20:53:41 EST 2000 i586 unknown
   2.03.8(1)-release

thanks/regards,

Tom.Rodman
@
jcm.com