This was on the north shore (Vancouver), under mostly deciduous trees. Unfortunately my trees are even worse than my berries, so I can't name any names...
I don't think M. bifolium is present locally -- though the closely related Maianthemum dilatatum is here (and that'd be my suggestion for this one).
I should perhaps mention that there was a sign nearby stating that the area had been settled and that many of the trees are non-indigenous. Would either of the suggested species be edible, and if so, perhaps they were also 'imported' along with the trees?
It's far more likely that it is the common native, M. dilatatum, as opposed to something that hitched a ride with trees (most of those trees will likely have been seed-planted or from North American grown nursery stock)