Hi everyone. Thanks for any help/advice.

Last year, we had a brand new Napoleon gas fireplace installed with marble surround. After literally the second use (first being only on/off to check operation) - with the fireplace being only for approximately 5 min to show it off to some family and friends, we were surprised to find a nasty brown stain on our marble the following morning.
I was able to remove some of the stain but a lot of it seems to have leeched into the marble. I am not too concerned about getting the stain out as we can refinish the marble but what I am curious is whether this is par for the course. I searched the web and these forums and read of marble surround staining with wood burning fireplaces but nothing regarding gas ones.
Was the fireplace installed incorrectly?