I believe I can taste fruit in most light lagers once they are warm and flat. I assumed it was a touch of munich in the recipe or some dark, fruity-like melanoidin from the boil. It could be the yeast, though, as a lot of commercial brewers lager warm with pressure to try and suppress ester formation. I don't think it is possible for replicating yeast to produce NO esters.
Every time I use WLP028, I swear it has fruity character to it. Then after 3-4 weeks at 32F, it loses it. All that really happens during this period is that the very fine, non-flocculant yeast cells fall out. I think they are the source of slight fruity flavors with some green beers. I suppose some flavor compounds could oxidize below detectable levels, but 32 is pretty cold.
Try it again after you have carbonated and lagered it for a few weeks. You may be surprised.