Shell script terminates when spawning and killing a background shell process

Hello,

I maintain a long bash script that runs fine on most platforms. However, 
on NetBSD it terminates before reaching the end.

I have reduced the case to the following ksh script that terminates when 
it kills its background process, this happens on NetBSD 9.3 and NetBSD 
10.1; when you don't think this script should print "SURVIVED"
this issue might be a feature though...


#! /bin/ksh

/bin/ksh -c "sleep 2" </dev/null &
pid0=$!

sleep 1

kill $pid0
wait

echo SURVIVED