Does standard input redirection within a variable work differently on RHEL 7 than older versions.

Hi there!

I faced an interesting issue. The following code works well on RHEL 5, but drops an error on RHEL7:

case $1 in
 a)
    *some code here*
    ;;
 b)
    *some code here*
    ;;
 c)
    v_rekord=$(sqlplus -s user/password

Error:
./t2.sh: line 64: unexpected EOF while looking for matching `)'
./t2.sh: line 120: syntax error: unexpected end of file

But it works well between backquotes:

case $1 in
 a)
    *some code here*
    ;;
 b)
    *some code here*
    ;;
 c)
    v_rekord=`sqlplus -s user/password

Is there an explanation or official statement for this?