BUG?: (or what's going on?) test for NL == NL fails (bash-4.3.39(3)-release)

[Linda Walsh]

printf "\n" |hexdump -C

00000000  0a

 printf "%s" $'\n'|hexdump -C

00000000  0a

 if [[ $(printf "\n") == $'\n' ]]; then echo T; else echo F; fi

F

----
just noticed the problem doesn't happen if I try to use '\t' (tab)

printf "\t" |hexdump -C

00000000  09

 printf "%s" $'\t'|hexdump -C

00000000  09

 if [[ $(printf "\t") == $'\t' ]]; then echo T; else echo F; fi

T