Parameter transformation `@A` on array member

Configuration Information [Automatically generated, do not change]:
Machine: aarch64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS: -march=armv8-a -O2 -pipe -fno-plt -fexceptions         -Wp,-D_FORTIFY_SOURCE=3 -Wformat -Werror=format-security         -fstack-clash-protection -DDEFAULT_PATH_VALUE='/usr/local/sbin:/usr/local/bin:/usr/bin' -DSTANDARD_UTILS_PATH='/usr/bin' -DSYS_BASHRC='/etc/bash.bashrc' -DSYS_BASH_LOGOUT='/etc/bash.bash_logout' -DNON_INTERACTIVE_LOGIN_SHELLS -std=gnu17
uname output: Linux localhost 4.14.116 #1 SMP PREEMPT Tue Mar 22 15:13:10 CST 2022 aarch64 GNU/Linux
Machine Type: aarch64-unknown-linux-gnu

Bash Version: 5.3
Patch Level: 9
Release Status: release

Description:
     For the array member `${x[1]@A}`, the output indicates that the member is an array

Repeat-By:
     $ x=(a b)
     $ echo "${x[1]@A}"
     declare -a x='b'
     $ # Expect like `declare x[1]='b'`