Why does sleep, when run in a shell script, ignore SIGINT?

When I run sleep manually, and then kill -INT it, sleep exits immediately. For example: $ /bin/sleep 60 & 4002356 $ kill -INT 4002356 + Interrupt /bin/sleep 60 $ ps -C sleep PID TTY TIME CMD $ However, when I do the same thing in a shell script, sleep ignores the SIGINT. For example: set -o xtrace echo /bin/sleep 10 & child="$!" /bin/sleep 0.1 ps -C sleep kill -TERM "$child" # SIGTERM /bin/sleep 0.1 ps -C sleep wait "$child" # will return immediately echo /bin/sleep 10 & child="$!" /bin/sleep 0.1 ps -C sleep kill -INT "$child" # SIGINT /bin/sleep 0.1 ps -C sleep wait "$child" # will wait for 9.8 seconds Why/how does sleep ignore SIGINT when I run sleep inside a shell script? I get the same behavior with dash and bash. My kernel is Linux 5.4.0.