C,
Well, in "theory" that outlet should be higher than the surface of the pool... So even if the light assembly was leaking it should not come out of the conduit going to the pool.
But the junction box/outlet could have been installed too low...
What I would do is remove the cover and outlet (Might want to turn the power off first) and expose the conduit coming from the pool. Then to confirm a leak, I would add water to the pool and see if it is obviously coming up the conduit.
I am no expert in this area, but the fix would be to take the light out and add some underwater sealant where the light wiring enters the conduit in the back of the light niche..
Thanks,
Jim R.