Sieve extprograms ?not exexuting?

[E.B.]

Hello, I was testing the extprograms plugin. I think I had it working
in the past, but many things have changed since then, so no use
trying to figure out where it broke - starting over again...

Debug-enabled log give me:
Apr 27 04:11:36 mail dovecot: lmtp(test at example.com): Debug:
qOGyA0DePHVaOyHEM/SpMA: sieve: action execute: running
program: test.sh
Apr 27 04:11:36 mail dovecot: lmtp(test at example.com): Debug:
waiting for program `/usr/local/etc/dovecot/sieve_globals/test.sh'
to finish after 0 seconds

So I guess it thinks it is running my script? But simple test script
does nothing. Here it is:

#!/bin/sh
read INPUT
INPUT="Hello world: $INPUT"
echo "$INPUT" >> /tmp/hello
echo "---------------------------" >> /tmp/hello

Permissions on this script file for now are rwxrwxrwx
But nothing goes to /tmp/hello at all. Script works when I run it
manually. I also tried without the "read" but I think that's required
isn't it? Anyway, what else can I do to debug this?

Dovecot 2.2.16
Pigeonhole 0.4.7