Detecting function circular references in bash

Why does the following idiom not work in bash 4.1.0?

if [[ "${FUNCNAME[*]:1/$FUNCNAME/}" != "${FUNCNAME[*]:1}" ]]

Here it is in context...

function isCircularRef_test () {
  #
  ### Seems like this should work but it does not.
  ###   if [[ "${FUNCNAME[*]:1/$FUNCNAME/}" != "${FUNCNAME[*]:1}" ]]; then ...
  ### It appears to fail silently and exit the script so neither 'then' nor
  ### 'else' branch executes.
  ### Storing the array into a temporary string variable works. Why necessary?
  #
  printf "%s\n" "VERSION #1"
  local _fna="${FUNCNAME[*]:1}"
  if [[ "${_fna/$FUNCNAME/}" != "${_fna}" ]]
  then
    printf "%s\n" "IS circular reference"
  else
    printf "%s\n" "IS not circular reference"
  fi
  #
  printf "%s\n" "VERSION #2"
  if [[ "${FUNCNAME[*]:1/$FUNCNAME/}" != "${FUNCNAME[*]:1}" ]]
  then
    printf "%s\n" "IS circular reference"
  else
    printf "%s\n" "IS not circular reference"
  fi
}

Output is...

VERSION #1
IS not circular reference
VERSION #2