Bash bug?

[Po Lu]

mapfile "-d " -t FOO <<<"1 2 3" ; for i in "${FOO[@]}"; do echo
"x${i}x"; done

gives:

x1x
x2x
x3
x

but since I specified -t, I would have expected that the delimiter be
removed from the end of each delimited input ``line''.

Is this a bug? If not, how do I do what I want?

Thanks.