For both 1.14.7(1) and 2.03.6(1)-release bash does not honous set -e
in subshells.  Consider this:

$ echo $BASH_VERSION
1.14.7(1)
$ (set -e; echo 1; false; echo 2) || echo 3
1
2
$ sh -c "set -e; echo 1; false; echo 2" || echo 3
1
3
$ bash2 -c "set -e; echo 1; false; echo 2" || echo 3
1
3
$ bash -c "set -e; echo 1; false; echo 2" || echo 3
1
3
$ bash2
$ echo $BASH_VERSION
2.03.6(1)-release
$ (set -e; echo 1; false; echo 2) || echo 3
1
2
$

Bash should behave in () correctly.  The correct answer is 1 3