I've tried looking through other posts for the answer to this, but didn't see anyone quite like mine, or definitive enough that I could say that one was helpful enough for me to diagnose.

The pilot light on my gas water heater has been going out today. I can re-ignite the pilot very easily, and As I watch, I am getting a steady blue stream hitting the thermo-couple, but when I come back a few hours later, it's out again. I just had the thermo-couple replaced and everything cleaned about a month ago by a professional. Any thoughts on the issue here?

Thanks!