Hi Thomas,
Thanks for looking into this, the problem is really somewhere around this tasks file. However I just tried faking the memory values directly inside the tasks file to something way higher and everything looks fine. I think the problem resides in registering the output of the "free -m" at the beginning of this file. There are also debug tasks which print registered values from the shell commands where we could take a closer look, see if it looks normal (stdout mainly).
This part that of the output that Seann provided seems particularly strange: Available memory ( {'failed': False, 'changed': False, 'ansible_facts': {u'max_mem': u'180746'}}MB )
Normally it should just show the exact value/string, here we're getting some dictionary from python most likely. I'd check if the latest version of ansible is installed and see if this can be reproduced if there was an update available.
If the issue persists please provide full log of the ansible run (ideally with -vvvv).
-Roman