Normal? No.
But not rare either.
Tiny dents can happen during construction, and if the builder spots them and determines that they don't matter, which they usually don't he'll body fill, or silver solder fill them prior to painting, and no will know or care. But he might have missed this one if it's small enough.
OTOH many paints used on frames are flexible enough to allow minor denting down the road without chipping or showing hairline cracks, so this might have happened at any time during the last year.
Top tube dents in steel frames are very common, with the most common cause being the handlebar swinging around and banging into the frame. You might check to see if the point on contact matches to confirm whether this might be what happened.
Years ago, many riders wound tape around the top tube to protect it from the handlebar. This practice would go in and out of fashion every few years, often coming back when a fellow club rider seriously dented a new frame in a minor crash. In any case, I never knew anyone to scrap a frame over a top tube dent, nor have I ever seen one lead to a failure.
If you can ignore it do so. If it bugs you camouflage it somehow, then ignore it.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.