Losing your job after Deferred Leave program

Hi there, I'm considering doing the deferred leave program so I can take 1 year off for travel. My supervisor said that there is no guarantee that I will have a job when I get back. A few other colleagues have told me they heard this as well but couldn't point to anything concrete. I looked through all the info online about the program and nothing is mentioned about losing your job. Is this true? Would they be required to place me in a different role if my job no longer exists when I'm back? I don't understand how deferred leave could be a benefit when you might be unemployed after using it. I emailed MyHR a few months ago but still haven't heard back.