Linux Background PHP process

Ok, this seems really weird. When I am running a php script from the command line with & at the end to run it in the background, it's immediately stopped. I tried it on another server and it worked as expected; the job is running in the background.

The PHP

#!/usr/bin/php
<?php
sleep (5);

Output on Server 1

[mk@li89-44 html]# ./test.php &
[1] 4938
[mk@li89-44 html]# jobs
[1]+  Running        ./test.php &

Output on Server 2

[mk@dev html]# ./test.php &
[1] 4938
[mk@dev html]# jobs
[1]+  Stopped        ./test.php &

On Server 2, I can get it in the background like so:

[mk@dev html]$ ./test.php
ctrl + z
[1]+  Stopped                 ./test.php
[mk@dev html]$ bg
[1]+ ./test.php &
[mk@dev html]$ jobs
[1]+  Running                 ./test.php

Also on Server 2, if i do something like wget "http://fileserver.com/largefile.gz" & it goes into the bg running as expected. Running nohup ./test.php & on server 2 also works as expected.

Both servers are running centos, different versions, and different versions of php as well. I dunno if that's relevant, or if this can be explained just by the way jobs, fg, bg work on linux.