I see nothing wrong with it. If I remember correctly the open voltage on a ballast is about 600 volts whether the supply is 120 or 277 volts. I would be more concerned with that than the input voltage.
It is legal but IMO a poor design.
Of all the large retail I have done all the 'high lighting' will be 277 and all the low lighting in shelving, displays etc will be 120.
It's not the voltage the worries me as much as the fault energy of the branch circuit.
Just Sunday I was at a Kohl's store fixing a reloc on the back of a 277 volt 2 x 4 trougher that failed turning about 25% of the back of the fixture black as coal, I fixed another one a few months ago that when the reloc failed it burnt a hole right through the fixtures KO plate without any actual contact.
I have some pictures of that one, I will try to find them.