The evap. test would need to run 3 times on separate trips with no failures
to turn the lamp out. This test may or may not run each time you drive the
vehicle. To my knowledge, Hyundai hasn't published the requirements for
the test to run.
You may want to take your car to autozone or anywhere else that will scan
it for free. The time for the lamp to come on is about right for a fuel
cap issue. Sometimes it's on tightly but crossthreaded, so the seal won't
hit the filler neck. If you have a code P0455, P0442, or P0456, you would
be okay to presume it was probably a fueling issue and reset the lamp to
see if it returns.
Also, make sure when receiving full service that the attendant doesn't
continue pumping significantly after fuel shut-off. This can cause fuel
to get into the charcoal canister and ruin it. If that's the case, I'd
expect a code P0449 or one of the others above. If you have a P0449, you
should take the car to be diagnosed.